John Calvin Commentary Psalms 137:2

"Upon the willows in the midst thereof We hanged up our harps." — Psalms 137:2 (ASV)

We hanged our harps upon the willows. He deplores the suspension of the songs of praise, which God had commanded in his Temple. The Levites were put in charge of the singing and led the people in this devotional exercise. If it is asked how they had carried their harps with them so far from their native land, this provides another proof mentioned by the Psalmist of their faith and fervent piety. For the Levites, when stripped of all their possessions, had preserved their harps at least as a precious item, to be used again for their original purpose when the opportunity arose.

We may suppose that those who truly feared God placed a high value on the remnants of his worship and showed the greatest care in preserving them until the time of their restoration. When willows are mentioned, this indicates the pleasantness of the riverbanks, which were planted with willows to provide coolness.

But the Psalmist says that these shady places, however delightful, could not dispel a grief too deeply seated to admit of common consolations or refreshment. As they sat on the riverbanks, covered with the shade of the trees, this was just the place where they might have been tempted to take up their harps and soothe their griefs with song. However, the Psalmist suggests that their minds were too heavily wounded by a sense of the Lord’s displeasure to deceive themselves with such superficial comforts.

He would even go further, suggesting that joy of a good and holy kind was suspended at this time. For although it was neither right nor wise to encourage their grief, we cannot wonder that the public singing of praises was given up until their return from captivity, since God’s chastisements called them to mourning and lamentation.