Psalm 119:105: "Your word is a lamp to my feet and a light to my path."
Psalm 119:111: "Your testimonies are my heritage forever, for they are the joy of my heart."
John 14:23: "Jesus answered him, 'If anyone loves me, he will keep my word, and my Father will love him, and we will come to him and make our home with him.'"
Luke 11:28: "But he said, 'Blessed rather are those who hear the word of God and keep it!'"
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The text is public domain:
God's Word is our great heritageAnd shall be ours forever;To spread its light from age to ageShall be our chief endeavor.Through life it guides our way,In death it is our stay.Lord, grant, while worlds endure,We keep its teachings pureThroughout all generations.
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Psalm 119:111 appears in the first two lines, and Psalm 119:105 appears throughout the next four, although most clearly in "Through life it guides our way."
The last few lines ("Lord, grant... We keep its teachings pure...") seem to come from both John 14:23 and Luke 11:28.
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"Lord, grant... We keep its teachings pure" also contains a grammatical ambiguity. "Teachings pure" can be understood either as a double accusative (so the sense is "Lord, grant that we maintain the purity of Your Word's teachings") or simply as a noun modified by a post-positive adjective (which can be reshuffled as "Lord, grant... we keep its pure teachings").