1 Corinthians 11:23-26: "23 For I received from the Lord what I also delivered to you, that the Lord Jesus on the night when he was betrayed took bread, 24 and when he had given thanks, he broke it, and said, 'This is my body which is for you. Do this in remembrance of me.' 25 In the same way also he took the cup, after supper, saying, 'This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me.' 26 For as often as you eat this bread and drink the cup, you proclaim the Lord's death until he comes."
Matthew 26:26-28: "26 Now as they were eating, Jesus took bread, and after blessing it broke it and gave it to the disciples, and said, 'Take, eat; this is my body.' 27 And he took a cup, and when he had given thanks he gave it to them, saying, 'Drink of it, all of you, 28 for this is my blood of the covenant, which is poured out for many for the forgiveness of sins.'"
John 1:1-3: "1 In the beginning was the Word, and the Word was with God, and the Word was God. 2 He was in the beginning with God. 3 All things were made through him, and without him was not any thing made that was made."
John 1:14: "14 And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth."
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The passages from 1 Corinthians 11 and Matthew 26 are the main sources for the hymn and are seen most clearly in the third and fourth verses.
The verses from John 1 (but mostly verse 14) appear near the end of the first verse ("Once on earth among us dwelling"), in the second verse ("condescending / To be born for us below, / He with us... dwelt"), and the beginning of the fourth verse ("Word made flesh...").
