John Calvin Commentary Jeremiah 9:1

"Oh that my head were waters, and mine eyes a fountain of tears, that I might weep day and night for the slain of the daughter of my people!" — Jeremiah 9:1 (ASV)

He follows the same subject. During times of tranquility, when nothing but joyful voices were heard among the Jews, he bewails, as one in the greatest grief, the miseries of the people; and not being satisfied with this, he says, Who will set, or make, my head waters, and my eye a fountain of tears? He intimates by these words that the ruin would be so dreadful that it could not be bewailed by a moderate or usual lamentation, since God’s vengeance would exceed common bounds and fill men with more dread than other calamities.

The meaning is that the destruction of the people would be so monstrous that it could not be sufficiently bewailed. Hence, it appears how hardened the Jews had become, for doubtless the Prophet had no delight in such comparisons, as though he wished rhetorically to embellish his discourse. But as he saw that their hearts were inflexible, and that a common way of speaking would be despised or would have no weight and authority, he was constrained to use such comparisons.

And today, there is no less callousness in those who despise God; for however Prophets may thunder, while God spares and indulges them, they promise themselves perpetual quietness. Hence, they ridicule and insult both God and his servants, as though they were treated too harshly.

Since, then, the same impiety prevails in the world now as formerly, we may learn from this what vehemence those whom God calls to the same office of teaching ought to use. Plain teaching, then, will always be deemed frigid in the world, unless it is accompanied with sharp goads, such as we find employed here by the Prophet. He adds—