John 16:20-22: "20 'Truly, truly, I say to you, you will weep and lament, but the world will rejoice. You will be sorrowful, but your sorrow will turn into joy. 21 When a woman is giving birth, she has sorrow because her hour has come, but when she has delivered the baby, she no longer remembers the anguish, for joy that a human being has been born into the world. 22 So also you have sorrow now, but I will see you again, and your hearts will rejoice, and no one will take your joy from you.'"
1 Peter 1:6-9: "6 In this you rejoice, though now for a little while, if necessary, you have been grieved by various trials, 7 so that the tested genuineness of your faith - more precious than gold that perishes though it is tested by fire - may be found to result in praise and glory and honor at the revelation of Jesus Christ. 8 Though you have not seen him, you love him. Though you do not now see him, you believe in him and rejoice with joy that is inexpressible and filled with glory, 9 obtaining the outcome of your faith, the salvation of your souls."
Psalm 30:11-12: "11 You have turned for me my mourning into dancing; you have loosed my sackcloth and clothed me with gladness, 12 that my glory may sing your praise and not be silent. O LORD my God, I will give thanks to you forever!"
Romans 8:38-39: "38 For I am sure that neither death nor life, nor angels nor rulers, nor things present nor things to come, nor powers, 39 nor height nor depth, nor anything else in all creation, will be able to separate us from the love of God in Christ Jesus our Lord."
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The text is public domain:
1 In Thee is gladnessAmid all sadness,Jesus, sunshine of my heart.By Thee are givenThe gifts of heaven,Thou the true Redeemer art.Our souls Thou wakest,Our bonds Thou breakest;Who trusts Thee surelyHas built securely;He stands forever:Alleluia!Our hearts are piningTo see Thy shining,Dying or livingTo Thee are cleaving;Naught can us sever:Alleluia!2 Since He is ours,We fear no powers,Not of earth nor sin nor death.He sees and blessesIn worst distresses;He can change them with a breath.Wherefore the storyTell of His gloryWith hearts and voices;All heav'n rejoicesIn Him forever:Alleluia!We shout for gladness,Triumph o'er sadness,Love Him and praise HimAnd still shall raise HimGlad hymns forever:Alleluia!
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The first three citations (John 16:20-22, 1 Peter 1:6-9, and Psalm 30:11-12) have a similar theme (rejoicing or gladness) that appears throughout the hymn but especially in the first line ("In Thee is gladness") and the end of the second verse ("All heav'n rejoices... We shout for gladness... And still shall raise Him / Glad hymns forever"). Additionally, Psalm 30:11 seems to be the basis for the line "He can change them with a breath" in the second verse.
The passage from Romans 8 bridges the end of the first verse and the beginning of the second: "Dying or living / To Thee are cleaving / Naught can us sever: / Alleluia! // Since He is ours, / We fear no powers, / Not of earth nor sin nor death."
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The lines "Who trusts Thee surely / Has built securely" in the first verse seem to refer to Matthew 7:24, where Jesus says that "'Everyone then who hears these words of mine and does them will be like a wise man who built his house on the rock.'"
