John Calvin on Lamentations 3:12

Here the Prophet introduces another metaphor, that God had shot him with arrows, as he was made a mark to them. Jeremiah has elsewhere often used the word מתרא, methera, for a prison; but here it means a mark at which arrows are leveled, and such is its meaning in Job 16:12, where there is a similar complaint made. The meaning is, that the people, in whose name Jeremiah speaks, had been like marks, because God had directed against them all his arrows. It is, indeed, a fearful thing when God aims at us, that he may discharge his darts and arrows in order to hit and wound us. But as God had so grievously afflicted his people, that he seemed to have poured forth all his vengeance, the Prophet justly complains that the people had been like marks for arrows.

Lamentations 3:13

13. He hath caused the arrows of his quiver to enter into my reins.

13. Induxit in renes meos filion pharetrae sum (id est, sagittas.)