The prologue of John's Gospel is quite unlike the Synoptics and describes the way in which Yah'shua (Jesus) brought life to men in a very esoteric way. It has been suggested that the ideas employed by John owe much to the influence of Hellenism for it is impossible to find any parallels in the Hebrew Scriptures. Perhaps, then, the reader of John's prologue should interpret "life" as being both esoteric (i.e. the inner life of a man) and exoteric (i.e. physical life itself) which I will now attempt to show.
John begins by describing Christ's pre-existence, thus setting Him apart from mere mortal man whose beginnings, in the Johnanine writings at least, are only described with physical birth. Christ is equated with Elohim (God) Himself, and John declares that He is in fact Elohim (God), the Word of the Father, or the executor of the Father, Yahweh. Christ is also creator of all things, and therefore by inference, we must assume that He possessed the power to create also, providing for His Creation its assimilating force which, for want of a better word, one might call "life". Specifically, though, He brought life to men, the animating force that allows us to move, breathe, think, etc.. But John is thinking in terms beyond mere physicality when he describes the life of man as an inner light. Indeed, the words "life" and "light" are often used interchangeably. What is this light? It is the means by which men can discern between good and evil, and which has been called by some his 'conscience'. So Christ gives to every man a life-force that not only animates his being but gives him the ability to discern between right and wrong.
We learn from John that this life force has never been overcome. This life, or light, shines in darkness, or death. Death, we are told, have never overcome it because it cannot comprehend it. This life is also used to describe the person of Yah'shua (Jesus) who is the exemplar of this light or life.
John the Baptist is called to prepare the way of Christ whom he refers to as "the light", disavowing any claim to be the light himself. He affirms that his mission is simply to bear testimony of Yah'shua (Jesus) and of the life that the Messiah brings to mankind. But with a touch of sadness, John points out that men are simply not prepared to receive the Christ, they don't want His light - His life - because they are ashamed to have their sins uncovered. Man's pride forbids him to confess his faults and so enable him to find new life in Yah'shua (Jesus). Indeed, because of the state of darkness in which they lived, the Jews simply did not recognise Him when He came even after He had subsequently performed miracles. But the latter may simply have been because there were many miracle-workers in Palestine at the time of Yah'shua (Jesus) of Nazareth.
How does Yah'shua (Jesus) give His followers this life force? The key is given by John who tells us that mankind must first receive the Messiah in their hearts, accept Him for what He claims to be, and believe in the power of His Name. For such as these Christ gave them the power to become the children of His Father by means of a spiritual rebirth, a baptism of the Ruach haQodesh (Holy Spirit) of which John's water-baptism was a type or symbol. To make his point, John stresses that this rebirth is not a physical one involving either blood or the will of the flesh, a problem Nicodemus was later to try and fathom out.
What qualities did the life of Christ offer to bring to men? John informs us that the fruits of this life were grace and truth, and a spiritual eye enabling the believers to behold the glory of the Son sent by the Father. The life then brought revelation, the ability to discern and understand spiritual things which mortal eyes could not behold. The Law of Moses was unable to bring this life for it was but a schoolmaster or forerunner of grace and truth, a set of carnal commandments that lacked the spiritual refinement of Christ's message and gifts.
So Yah'shua (Jesus) brought life to men both spiritually and physically - physically as the Creator of the Universe and all that is therein, including man himself - and spiritually by giving birth to men in their hearts through faith in His name and an acceptance of His mission which culminated in the complete redemption of mankind. Thus, as John was later to write, Christ was, and is, the life and light of men by virtue of His Godhood. And of the Gospel writers, perhaps John understood this best.