Psalms 137:5

What we love, we love to think of. Those that rejoice in God, for his sake make Jerusalem their joy. They stedfastly resolved to keep up this affection. When suffering, we should recollect with godly sorrow our forfeited mercies, and our sins by which we lost them. If temporal advantages ever render a profession, the worst calamity has befallen him. Far be it from us to avenge ourselves; we will leave it to Him who has said, Vengeance is mine. Those that are glad at calamities, especially at the calamities of Jerusalem, shall not go unpunished. We cannot pray for promised success to the church of God without looking to, though we do not utter a prayer for, the ruin of her enemies. But let us call to mind to whose grace and finished salvation alone it is, that we have any hopes of being brought home to the heavenly Jerusalem.

If I forget thee, O Jerusalem, let my right hand forget her cunning. To sing Zion's songs for the pleasure of Zion's foes, would be to forget the Holy City Each Jew declares for himself that he will not do this; for the pronoun alters from "we" to "I." Individually the captives pledge themselves to fidelity to Jerusalem, and each one asserts that he had sooner forget the art which drew music from his harp strings than use it for Babel's delectation. Better far that the right hand should forget its usual handicraft, and lose all its dexterity, than that it should fetch music for rebels out of the Lord's instruments, or accompany with sweet skill a holy Psalm desecrated into a common song for fools to laugh at. Not one of them will thus dishonour Jehovah to glorify Belus and gratify his vetaries. Solemnly they imprecate vengeance upon themselves should they so false, so faithless prove.