No man hath seen God at any time - This declaration is probably made to show the superiority of the revelation of Jesus above that of any previous dispensation. It is said, therefore, that Jesus “had an intimate knowledge of God,” which neither Moses nor any of the ancient prophets had possessed. God is invisible: no human eyes have seen him; but Christ had a knowledge of God which might be expressed to our apprehension by saying that he saw him. He knew him intimately and completely, and was therefore fitted to make a fuller manifestation of him. See John 5:37; John 6:46; 1 John 4:12; Exodus 33:20; John 14:9. This passage is not meant to deny that men had witnessed “manifestations” of God, as when he appeared to Moses and the prophets (compare Numbers 12:8; Isaiah 6:1-13); but it is meant that no one has seen the essence of God, or has “fully known God.” The prophets delivered what they “heard” God speak; Jesus what he knew of God as his equal, and as understanding fully nature.
The only-begotten Son - See the notes at John 1:14. This verse shows John’s sense of the meaning of that phrase, as denoting an intimate and full knowledge of God.
In the bosom of the Father - This expression is taken from the custom among the Orientals of reclining at their meals. See the notes at Matthew 23:6. It denotes intimacy, friendship, affection. Here it means that Jesus had a knowledge of God such as one friend has of another - knowledge of his character, designs, and nature which no other one possesses, and which renders him, therefore, qualified above all others to make him known.
Hath declared him - Hath fully revealed him or made him known. Compare Hebrews 1:1, Hebrews 1:4. This verse proves that Jesus had a knowledge of God above that which any of the ancient prophets had, and that the fullest revelations of his character are to be expected in the gospel. By his Word and Spirit he can enlighten and guide us, and lead us to the true knowledge of God; and there is no true and full knowledge of God which is not obtained through his Son. Compare John 14:6; 1 John 2:22-23.