John 8:12   When Jesus spoke again to the people, he said, "I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life."

4.1 1 Light - Physical

Light is something special in the Physical world.  In the olden days it was thought that light travel with infinite velocity.   Therefore it was an apt symbol for the omnipresence of  God.  The word implies that God is everywhere at all times.  Now we know that light travels with finite speed in space as a group wave though it may have any speed in phase wave.  A pure frequency light wave  without beginning or end can have any speed.  However when it becomes a composite wave, the group velocity becomes finite.  Strange because that is what we have been discussing as the relation between Nirguna-Brahman and Saguna Brahman.  Light becomes a Physical reality only in group.  Again with the relativity we have a strange situation.  The velocity of light is the maximum speed any material particle can have.  As the speed of a body increase, its mass increases and it reduces its width in the direction of motion.  If the particle reaches the speed of light (which is 3 and 8 zeroes after it in meters) it thickness becomes zero and mass becomes infinitely large.  If the speed can increase beyond the speed of light the dimension of existence of the matter is changed.  Mass becomes negative.  Physicist calls such particles as Tachyons.  However experiments could not detect any physical particle with such properties.  We enter into a different dimension all together.  Light is the only reality that exists in all these dimensions.  If we can travel on the wings of light then  time will cease.  There will be no change for us.  What a good definition and an excellent symbol for the Unchanging and Everlasting, Omnipresent, and Omniscient God.  For God time do not have any meaning.   Man as material being  exists in time.  Light Person is not in time.

Light is not a person.  If we add this personality we get the description of God.

4.12  The Binding Force
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Everybody knows of the famous mass energy relation.  E = m c
Energy and mass are related through the velocity of light.  It is the essence of matter and energy.
Acts 17:28  'For in him we live and move and have our being.'
The binding force within the atom is electromagnetic interaction and Light (Photon) is the materialization of this binding energy.  It is light that holds together the atoms.  Jesus is the creator of the Universe and it is he that holds the universe together. The immanence of God is depicted in this picture.
John 1:3  Through him all things were made; without him nothing was made that has been made.
Col 1:17  He is before all things, and in him all things hold together.
Heb 1:3  The Son is the radiance of God's glory and the exact representation of his being, sustaining all things by his powerful word.
Just as light holds together matter, love holds together all life.  When love is removed and selfishness comes in, it becomes evil and  this destroys man.
John 1:1   In the beginning was the Word, and the Word was with God, and the Word was God.
John 1:2   He was with God in the beginning.
John 1:3   Through him all things were made; without him nothing was made that has been made.
John 1:4   In him was life, and that life was the light of men.
John 1:5   The light shines in the darkness, but the darkness has not understood it.
John 1:6   There came a man who was sent from God; his name was John.
John 1:7   He came as a witness to testify concerning that light, so that through him all men might believe.
John 1:8   He himself was not the light; he came only as a witness to the light.
John 1:9   The true light that gives light to every man was coming into the world.

Here light is put in conjunction with life.  Light is the energy that binds together that brings forth life.  If the directed activity of  binding is not there, atoms are not formed, atoms do not form molecules, molecules do not form organisms and there will  be no life.  Creation cannot take place without Jesus.  As it was true in the beginning, so is it true in the new creation of New Man.

4.13   There is None Beside Me.

Another uniqueness of light particle, which is called Photon is that, it has no opposite.  There are no antiphoton

There is no antilight. “I am God, there is none beside me.”  There is no other God.

1John 1:5   This is the message we have heard from him and declare to you: God is light; in him there is no darkness at all.

Here the comparison is to emphasize the fact that there is no darkness in God.

Darkness  - is not real.  Darkness  is the absence of light. Darkness is not the opposite of light.  It is not a real entity.   Evil is not a reality -- it is only a moral reality.  It is lack of goodness. God did not create evil -- indeed by nature he cannot.  Then how come it is there.   Evil is the misuse of ourselves, of things given to us, misuse of our privileges etc.   Satan is not a negative God.  God does not fight with Satan.   Satan is an evil being -- a person who is evil.  Satan is a creature of God who went against God and is the leader of the disobedient.  Most of us have the mistaken notion that God has to fight Satan to defeat him.  God does not have to.  God wants us to defeat Satan because the evil is in us.  We have to overcome it for ourselves.

Rom 16:20  The God of peace will soon crush Satan under your feet. The grace of our Lord Jesus be with you.

James 1:13  When tempted, no one should say, "God is tempting me." For God cannot be tempted by evil, nor does he tempt anyone;

James 1:14  but each one is tempted when, by his own evil desire, he is dragged away and enticed.
 How do we defeat Satan?  How do we bring light in dark place?  You cannot remove it by hand.  You have to bring light into that area.  Bring God into all the areas of life so that evil is overcome.  Satan is defeated when the Mafia leader Satan can not get his way.
 

4.14  The Trinity

There is however another striking similarity between God’s dimensional property and the Photon’s dimensional property of spin.  The spin of the Photon (We really do not know what this means.) is 1 and it is a Boson.  This means that for someone outside of it looking at the photon it can have any of the following spin states: +1, 0 or -1  with reference to his own system of reference.  This is a Trinitarian comparison.  The fact that it is a Boson means that we cannot really distinguish between one photon from another.  They are identical in character, nature and indistinguishable.  I may be stretching the symbolism too far.  But one cannot over look this striking fact.

4.15.  Multidimensionality

Light is the only massless particle that we know.  Indeed it cannot stop moving because of this.  Particles that travel with speeds less than light form the material world.  Particles that travel with speeds greater than light cannot exist in this material world.  They exist (at least theoretically) in their world  of negative mass and their own laws.  They travel backwards in time, if time has any many there.  But light exists in both these worlds.

But we should be careful not to equate light with God.  God is not light -- the physical quantity.  It is a good symbol of God.  God is beyond  light.  Light was created by God.

Gen 1:3  And God said, "Let there be light," and there was light.

Darkness destroys us because we do not know where we are and where we are going -- the works of darkness

4.2  God beyond light

4.21  God who dwell in a dark cloud

Physical light is a creation of God.  God is beyond any of his creations.  One cannot understand God.  Man is incapable of understanding God.  This is expressed in symbolic terms as follows. God is not knowable.
2Chr. 6:1   Then Solomon said, "The LORD has said that he would dwell in a dark cloud;
1Kgs. 8:12   Then Solomon said, "The LORD has said that he would dwell in a dark cloud;
2Sam. 22:10   He parted the heavens and came down; dark clouds were under his feet.
Ps. 18:11   He made darkness his covering, his canopy around him-- the dark rain clouds of the sky.
Ps. 97:2   Clouds and thick darkness surround him; righteousness and justice are the foundation of his throne.
 
4.22  Light is Energy.

Light makes us see things clearly so that we may be able to walk without falling.  It gives us knowledge.  It is one of the means of  perception.  It is the major means of communication.

2Cor. 4:6   For God, who said, "Let light shine out of darkness," made his light shine in our hearts to give us the light of the knowledge of the glory of God in the face of Christ.

Laser beams are well known today.  They are light beans with limited frequency range and have large amplitudes.  These  can be used to cut very finely and are  used in cutting diamonds and used surgery as a micro knife and also to   clean surfaces from dirt. However if misused it can destroy .

4.3  Jesus as Light:  that which shows the true nature.
 
John 9:5   While I am in the world, I am the light of the world."

Here Jesus is referring to the fact that he came into the world to show how sinful mankind is and to show the way.  This is how he explains this in John 3

John 3:19  This is the verdict: Light has come into the world, but men loved darkness instead of light because their deeds were evil.

John 3:20  Everyone who does evil hates the light, and will not come into the light for fear that his deeds will be exposed.

John 3:21  But whoever lives by the truth comes into the light, so that it may be seen plainly that what he has done has been done through God."

This is what Jesus did while he was on the earth.  When Jesus left the world he did send another counselor who does the same thing.

John 16:7  But I tell you the truth: It is for your good that I am going away. Unless I go away, the Counselor will not come to you; but if I go, I will send him to you.

John 16:8  When he comes, he will convict the world of guilt in regard to sin and righteousness and judgment:

John 16:9  in regard to sin, because men do not believe in me;

John 16:10  in regard to righteousness, because I am going to the Father, where you can see me no longer;

John 16:11  and in regard to judgment, because the prince of this world now stands condemned.

4.4  Jesus and Light

All life depends on light from the sun (with the possible excepts of a few organisms near deep sea vents). Photosynthetic organisms are at the bottom of the food chain and provide the chemical energy that the rest use. They also provide the oxygen needed for respiration.

Given how important light is to life, it is no wonder that there are many types of interactions between light and living organisms. Broadly speaking, these interactions can be divided into three functional groups:

1. Visualization and Spatial orientation. Plants and microorganisms use light to orient themselves spatially and to guide their movements or growth. Higher animals are capable of using light to image their surroundings. Nature has developed sensitive photoreceptors, such as the rhodopsin in your eye, which can convert light energy into a chemical signal.

Without Jesus, we become disoriented, incapable knowing the direction of our movement.  We become random and blind.

2. Temporal orientation. Most animals and plants (including people) also use light to set their internal clocks. From the way that the light changes with time, organisms can not only tell whether it is night or day but also what time of year it is. For example, many plants use this to determine when to flower. Again sensitive biological photoreceptors are used for this purpose.

Time and existence itself will have meaning only in Jesus

3. Conversion of light energy to chemical energy. The dominant biological process, which converts light energy into chemical energy, is photosynthesis In addition, there are other light-powered processes in nature. For example, the enzyme DNA photolyase uses light energy to power the chemistry required for the repair of UV-damaged DNA.

Jesus is the strength and energy giver of life.

The true nature of Jesus is somehow connected with light as is seen in the following theophanies.
 
4.41  At Transfiguration
Matt. 17:2   There he was transfigured before them. His face shone like the sun, and his clothes became as white as the light.

4.42  Appearance to Saul
2Cor. 4:6   For God, who said, "Let light shine out of darkness," made his light shine in our hearts to give us the light of the knowledge of the glory of God in the face of Christ.

4.43  The Word of God as light - Scripture

2Pet. 1:19   And we have the word of the prophets made more certain, and you will do well to pay attention to it, as to a light shining in a dark place, until the day dawns and the morning star rises in your hearts.

4.5  Purpose of Jesus’ incarnation:
 
Isa. 9:2   The people walking in darkness have seen a great light; on those living in the land of the shadow of death a light has dawned.
 
Lk.1.79 “To give light to them that sit in darkness in the shadow of death, to guide our feet into the day of peace.”  connection with birth of Jesus

 Purpose of light is to make us see   -- to see the defects, pitfalls, mistakes, to see us as we are, to see others as they are and the world clearly.  But light does not in itself condemn us- we condemn ourselves. Many people do miss this point.  God is not a killer.  He is gracious, compassionate and full of mercy.  It this aspect that is reveled in Jesus
 
John 3:19   This is the verdict: Light has come into the world, but men loved darkness instead of light because their deeds were evil.
John 3:20   Everyone who does evil hates the light, and will not come into the light for fear that his deeds will be exposed.
John 3:21   But whoever lives by the truth comes into the light, so that it may be seen plainly that what he has done has been done through God."
 
Acts 26:18   to open their eyes and turn them from darkness to light, and from the power of Satan to God, so that they may receive forgiveness of sins and a place among those who are sanctified by faith in me.'

The purpose of his incarnation is to redeem mankind from the power of Satan--to show the path, the way out
John 8:12   When Jesus spoke again to the people, he said, "I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life."
John 12:35   Then Jesus told them, "You are going to have the light just a little while longer. Walk while you have the light, before darkness overtakes you. The man who walks in the dark does not know where he is going.
John 12:36   Put your trust in the light while you have it, so that you may become sons of light." When he had finished speaking, Jesus left and hid himself from them.
 
4.6  You are the light of the world

Jesus goes on to say that those who believe and follow him are the light of this world.  He was the light while he was on the earth.  When Jesus left the earth, he has anointed his elect to be the light of this world
Jesus is the source of light -- you are the light by reflection
Matt. 5:14    "You are the light of the world. A city on a hill cannot be hidden.
Matt. 5:15   Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house.
Matt. 5:16   In the same way, let your light shine before men, that they may see your good deeds and praise your Father in heaven.
1Pet. 2:9   But you are a chosen people, a royal priesthood, a holy nation, a people belonging to God, that you may declare the praises of him who called you out of darkness into his wonderful light.

There are two types of reflection;
  1.  scattering:  Here light falls on the object and object scatters it in all directions.  We see objects by their scattered light.  We can see the paper because it scatters the light.
   2. specular reflections. Here the light falling on it is reflected in an orderly fashion.  It is not mixed one into the other.  We do not see the reflecting object, but we see the light source.  This is what a mirror does.

You can become a mirror so that Jesus can be seen in you  When you project yourself it ceases to be a mirror you are scattering the light.    When you become the object seen through your ministry people will rarely see Jesus through you.  The more orderly you reflect Jesus in your life more clearly others will be able to see Jesus.  The less light you scatter,  the more you are filled with the word and transformed into the image of Jesus, the more of Jesus will be seen by others.  Transformation from an opaque, rough surface to the smooth, polished mirror is accomplished by abiding in the word of god and living in the spirit.

If you are blind   light does not work for you.   Those who are spiritually blind can never see the beauty of Jesus.  In fact they are so self-centered that they cannot see others at all.
Luke 11:34   Your eye is the lamp of your body. When your eyes are good, your whole body also is full of light. But when they are bad, your body also is full of darkness.

Spiritual discerning
1Cor. 1:18   For the message of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God.

1Cor. 1:19   For it is written: "I will destroy the wisdom of the wise; the intelligence of the intelligent I will frustrate."

1Cor. 1:20   Where is the wise man? Where is the scholar? Where is the philosopher of this age? Has not God made foolish the wisdom of the world?

A  Hermeneutical Note:
I have used our modern understanding of Light to interpret the meaning of “I am the light of the world”.
These interpretations are feasible provided we agree that Jesus being God he knew about these facts and intended to be understood in time.  At least in some cases of parables he did clearly state that.  This can be seen in Matthew 13 Kingdom Parables where Jesus says:

Mat 13:35  So was fulfilled what was spoken through the prophet: "I will open my mouth in parables, I will utter things hidden since the creation of the world."

Was  he in this place speaking the wonderful things hidden since the creation of the world?
Mat 13:52  He said to them, "Therefore every teacher of the law who has been instructed about the kingdom of heaven is like the owner of a house who brings out of his storeroom new treasures as well as old."
Are we privileged to bring out these hidden truths in this last age?

But it is quite possible that this is not the case for every parable.

Parables and similes are used in teaching to explain a concept.  These similes should not be pressed too far the extend of allegory.  This will be dangerous as we will be imposing new meanings not meant in the situation. This is particularly true of the didactic parables.  Most parables are culture sensitive and context sensitive and will yield very disastrous results if interpreted out of the cultural and historical context.

Did Jesus really mean these when he said these things to his disciples at that time?  Did he intend us to reinterpret it the way we do now?   I leave it to the reader.  But they are certainly interesting and encouraging to the believer.