The Word–Jn.1:18 
“No man hath seen God at any time; the only begotten Son, which is in the bosom of the Father, he hath declared him.”
We have already seen some of the attributes of the Word, in that he is full of grace and truth. But now we see the character, nature and essence of the Word since he is the only begotten of the Father. The title ‘the Word’ conveys to us the disclosure of God’s mind but as the only begotten Son we see the disclosure of God’s heart.
John says that none of the human race has ever looked upon God in his essential glory (what he is ontologically). Not Adam in innocence, not Abraham the friend of God, nor David the man after God’s own heart - none. These men saw God in different forms, whether in theophanies, visions or dreams, but none saw him as he is. No one has seen God in his intrinsic glory.
Even Moses who spoke “face to face” (Ex. 33:11) with God was told “no man can see me, and live” (Ex.33:20). God is unspeakably holy, fearfully glorious and a consuming fire. Sinful, defiled, mortal eyes cannot look upon him. We do well to remember this simple yet profound fact - he is God, we are men. He is “the King eternal, immortal, invisible, the only God ... who alone possesses immortality and dwells in unapproachable light, whom no man has seen or can see” (1 Tim. 1:17, 6:16 NASB). Because God is holy, we could never have looked upon him, because he is spirit and invisible, we would never have looked upon him.
And yet, God in his transcendence and inscrutability has revealed himself in Son. The Lord Jesus is “the image of the invisible God” (Col. 1:15), he is not just an outward appearance of God but God manifest in flesh. As the only begotten Son his relationship with the Father has known no beginning; eternally begotten, he is the delight of the Father’s heart. He is perfectly qualified to reveal God. He is essentially the same and his work is to make known the character, nature and being of the Father. John’s Gospel is full of such references:
“Not that any man hath seen the Father, save he which is of God, he hath seen the Father” (Jn. 6:46)
“He that seeth me seeth him that sent me” (Jn. 12:45)
“He that hath seen me hath seen the Father” (Jn. 14.10)
As the Word he communicates the mind of God, as the only begotten he communicates the love of God. This is the Son of his love “declaring God according to His own competency of nature, and the fulness of His own intimacy with the Father”[i].
Though the Lord Jesus was here on earth there was no distance between the Father and Son. John explains metaphorically that the Son is always “in the bosom of the Father”. This is where he has been from all eternity. It reminds us of the nearness, intimacy and filial unity within the Godhead. Geographical distance did not lessen the ability of the Son to reveal all that the Father was. Though on earth he was still united to the Father in heaven, says John “no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven” (Jn. 3.13). Whether at the cradle or the cross, the Father - Son union was inseparable.
In the dispensation of law God dwelt in thick darkness, there were barriers that prevented access to his presence; people knew God in a partial and fragmentary way. With the coming of Christ the shadows have gone and the jigsaw of divine revelation has come together. The Lord Jesus has fully told God out; like a narrator or teacher he has explained the character and nature of the invisible God. The mode of communication was not just verbal but visual, to see the Lord Jesus was to see God. He is the embodiment of God’s love, righteousness, holiness and mercy. All that God is, is seen in Christ.
Though we have never seen him with physical eyes, we know him by faith; he promised as much saying, “blessed are they that have not seen, and yet have believed” (Jn. 20:29). However, one day faith will give way to sight, when these mortal bodies are changed and “we shall see him as he is” (1 Jn. 3:2). Hallelujah. Maranatha.
[i] An Exposition of the Gospel of John (William Kelly), http://www.stempublishing.com/authors/kelly/2Newtest/John_pt1.html#a1