The Word became flesh and made his dwelling among us. We have seen his glory, the glory of the one and only, who came from the Father, full of grace and truth.
I have been dreading how to unpack this verse. There is so much in it to ponder. First, it affirms the incarnation. If it were not obvious by now, the Word is Jesus. God in human form. There is no nativity narrative in John's Gospel, but he undoubtedly had those of Matthew and Luke before him.
Second, the word 'became' should not be taken to mean a metamorphosis, like a tadpole becoming a frog or a caterpillar becoming a butterfly. It really means adding something to what was there already. He added humanity to divinity. He only laid aside his Majesty.
Third, he made his dwelling among us - like pitching a tent. It was a temporary affair, unlike his humanity. He gave up his dwelling among us when he ascended into heaven, but he didn't give up being human. He still feels for us.
Fourth, his glory. I wondered if John was thinking about the Mount of Transfiguration. He was one of the privileged three who witnessed the appearance of his face changing so that it shone like the sun and his clothes becoming as bright as a flash of lightning, dazzling white, whiter than anyone in the world could bleach them, when a voice came from a cloud proclaiming, "This is my son, whom I love." Was that the glory that John meant? Or was it the glory of his wonderful life, death and resurrection?
Fifth, what does it mean, 'the one and only who came from the Father'? The KJV has 'the only begotten of the Father'. This seems to be the natural meaning and the change is only to give wriggle room to those who object to the idea of Jesus as the son of God. His sonship derives not from his miraculous conception and birth, nor was the title conferred upon him as recognition of his atoning sacrifice. He was the Son by his nature and from eternity. He is the beloved Son in whom the Father is well pleased. Son of God may be offensive to Moslems; they are repelled by the idea of a God having sex with a woman, like some Zeus from Greek mythology. It is rather, a metaphor for the intimate relationship between the first and second persons of the Trinity.
Sixth, full of grace and truth. Grace because the message he brought and the blessing he procured were of unmerited favor for the guilty. Truth because he was the final reality; the truth behind all the shadows that preceded him.