Isaiah 61:10: "I will greatly rejoice in the LORD; my soul shall exult in my God, for he has clothed me with the garments of salvation; he has covered me with the robe of righteousness, as a bridegroom decks himself like a priest with a beautiful headdress, and as a bride adorns herself with her jewels."
Revelation 19:7-8: "7 'Let us rejoice and exult and give him the glory, for the marriage of the Lamb has come, and his Bride has made herself ready; 8 it was granted her to clothe herself with fine linen, bright and pure' - for the fine linen is the righteous deeds of the saints."
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."
John 6:35: "Jesus said to them, 'I am the bread of life; whoever comes to me shall not hunger, and whoever believes in me shall never thirst.'"
John 6:48-51: "48 'I am the bread of life. 49 Your fathers ate the manna in the wilderness, and they died. 50 This is the bread that comes down from heaven, so that one may eat of it and not die. 51 I am the living bread that came down from heaven. If anyone eats of this bread, he will live forever. And the bread that I will give for the life of the world is my flesh.'"
John 6:57-58: "57 'As the living Father sent me, and I live because of the Father, so whoever feeds on me, he also will live because of me. 58 This is the bread that came down from heaven, not like the bread the fathers ate and died. Whoever feeds on this bread will live forever.'"
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Only some of the stanzas are public domain:
2 Hasten as a bride to meet Him,And with loving rev'rence greet Him.For with words of life immortalHe is knocking at your portal.Open wide the gates before Him,Saying, as you there adore Him:Grant, Lord, that I now receive You,That I nevermore will leave You.
3 He who craves a precious treasureNeither cost nor pain will measure;But the priceless gifts of heavenGod to us has freely given.Though the wealth of earth were proffered,None could buy the gifts here offered:Christ's true body, for you riven,And His blood, for you once given.
6 Jesus, sun of life, my splendor,Jesus, friend of friends, most tender,Jesus, joy of my desiring,Fount of life, my soul inspiring:At Your feet I cry, my maker,Let me be a fit partakerOf this blessèd food from heaven,For our good, Your glory, given.
7 Lord, by love and mercy driven,You once left Your throne in heavenOn the cross for me to languishAnd to die in bitter anguish,To forego all joy and gladnessAnd to shed Your blood in sadness.By this blood redeemed and living,Lord, I praise You with thanksgiving.
8 Jesus, bread of life, I pray You,Let me gladly here obey You.By Your love I am invited,Be Your love with love requited;By this Supper let me measure,Lord, how vast and deep love's treasure.Through the gift of grace You give meAs Your guest in heav'n receive me.
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Isaiah 61:10 and Revelation 19:7-8 both seem to be present in the first two verses, particularly the first line of each: "Soul, adorn yourself with gladness" and "Hasten as a bride to meet Him."
The passage from 1 Corinthians 11 appears first at the end of the third verse ("Christ's true body, for you riven, / And His blood, for you once given") and is also present in most of the following verses. The selections from John 6 overlap with 1 Corinthians 11 to some degree, but there are also parts of the hymn that are drawn specifically from them: the phrase "bread of life" appears in the fourth and eight verses, and the phrase "food from heaven" is in the sixth.
Perhaps coincidentally, the line "Open wide the gates before Him" in the second verse bears some resemblance to Psalm 24:7: "Lift up your heads, O gates! And be lifted up, O ancient doors, that the King of glory may come in."
The lines "By this Supper let me measure, / Lord, how vast and deep love's treasure" in the eighth verse may refer to Ephesians 3:17b-19: "that you, being rooted and grounded in love, 18 may have strength to comprehend with all the saints what is the breadth and length and height and depth, 19 and to know the love of Christ that surpasses knowledge, that you may be filled with all the fullness of God."
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To some degree, the alliteration in the line "He, though heav'nly, high, and holy" in the first verse illustrates God's perfection.