John Calvin Commentary Psalms 137:5

"If I forget thee, O Jerusalem, Let my right hand forget [her skill]." — Psalms 137:5 (ASV)

If I shall forget thee, O Jerusalem! This confirms what was said in the previous verse and leaves us in no difficulty to understand what the Psalmist meant by it. For here God’s people declare, and with the solemnity of an oath, that the remembrance of the holy city would be ever engraved upon their hearts and never, under any circumstances, effaced.

Having spoken of song and of the instruments of music, the Psalmist’s appeal is made in terms which correspond — that his hand would forget its cunning, and his tongue cleave to his palate, or the roof of his mouth. The meaning is, that the Lord’s people, while they mourn under personal trials, should be still more deeply affected by public calamities which befall the Church, it being reasonable that the zeal of God’s house should have the highest place in our hearts and rise above all mere private considerations.

The second part of the sixth verse some interpret — If this is not my chief joy to see Jerusalem once more in a flourishing condition. Others — Joy will never enter my heart again until I am gladdened by the Church’s restoration. Both meanings are in my opinion comprehended in the words of the Psalmist.

The one cannot be separated from the other; for if we set Jerusalem above our chief joy, the height of this joy must arise from the consideration of its prosperity, and, if this is the case, the grief we feel under its calamities will be such as effectually to shut out all worldly joys.