John 1:1: "In the beginning was the Word, and the Word was with God, and the Word was God."
John 1:4: "In him was life, and the life was the light of men."
John 1:10-14: "He was in the world, and the world was made through him, yet the world did not know him. He came to his own, and his own people did not receive him. But to all who did receive him, who believed in his name, he gave the right to become children of God, who were born, not of blood nor of the will of the flesh nor of the will of man, but of God.
"And the Word became flesh and dwelt among us, and we have seen his glory, as of the only Son from the Father, full of grace and truth."
Colossians 1:15-20: "He is the image of the invisible God, the firstborn of all creation. For by him all things were created, in heaven and on earth, visible and invisible, whether thrones or dominions or rulers or authorities - all things were created through him and for him. And he is before all things, and in him all things hold together. And he is the head of the body, the church. He is the beginning, the firstborn form the dead, that in everything he might be preeminent. For in him all the fullness of God was pleased to dwell, and through him to reconcile to himself all things, whether on earth or in heaven, making peace by the blood of his cross."
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The first verse contains elements from both Biblical citations: "Eternal Word made flesh and bone" from John 1 and "The fullness of His deity" from Colossians 1.
"To mend what sin had marred" in the second verse seems to come from the Colossians text, specifically "to reconcile to himself all things." Jesus' coming "as life and light" is from John 1:4.
The third verse comes primarily from John 1:10-14. "The world did not know him" and "his own people did not receive him" are represented in "He was not received." The second half of the verse basically just paraphrases "To all who did receive him, who believed in his name, he gave the right to become children of God, who were born, not of blood nor of the will of the flesh nor of the will of man, but of God":
And some His name believed.
To these He gave the right to be
The heirs of heav'n above,
Born not of human ancestry
But born of God in love.
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I found more than a few references to Biblical texts that aren't cited.
The line "And Paradise was barred" in the second verse refers to Genesis 3:24: "He drove out the man, and at the east of the garden of Eden he placed the cherubim and a flaming sword that turned every way to guard the way to the tree of life."
"For when the time was full and right / God sent His only Son" - also in the second verse - comes from Galatians 4:4: "But when the fullness of time had come, God sent forth his Son...."
"As God with us, Emmanuel" in the fourth verse references Matthew 1:23 (which quotes Isaiah 7:14): "'Behold, the virgin shall conceive and bear a son, and they shall call his name Immanuel' (which means, God with us)."
The lines "Though rich, You willingly became / One with our poverty" in the fourth verse bear some resemblance to Philippians 2:5-7: "Have this mind among yourselves, which is yours in Christ Jesus, who, though he was in the form of God, did not count equality with God a thing to be grasped, but made himself nothing, taking the form of a servant, being born in the likeness of men." The text doesn't mention poverty specifically, but it has the same structure and same general idea as the lines in the hymn: although Jesus had an exalted position, He accepted a lowlier one among us.
