Charles Ellicott Commentary Psalms 87:7

"They that sing as well as they that dance [shall say], All my fountains are in thee." — Psalms 87:7 (ASV)

The literal sense of this most obscure verse is—
“And singers as trumpeters
All my springs in Thee,”

We may paraphrase this, keeping in the same line with the rest of the psalm: For such a one (celebrating his birthday, Genesis 40:20; Matthew 14:6) the singers and musicians will sing (to Zion), “All my offspring is in You.”

Not only is it a boast to have been born in Zion, but in the genuine Hebrew spirit, the boast is continued into future generations, and the Hebrew of the Hebrews exults in addressing the sacred city as the cradle of his family.

For this figurative application of the word “springs” to posterity, compare Psalms 68:26; Isaiah 48:1; Proverbs 5:16.