John Calvin Commentary Lamentations 3:63

"Behold thou their sitting down, and their rising up; I am their song." — Lamentations 3:63 (ASV)

The Prophet still repeats the same thing, only in other words. He had spoken of the ambushes, conspiracies, and speeches of his enemies; he now adds that nothing was hidden from God. By sitting and rising, he means all the actions of life, as when David says,

You know my sitting and my rising (Psalms 139:2).

That is, whether I rest or walk, all my actions are known to You. By rising, then, the Prophet denotes here, as David did, all the movements or activities of men; and by sitting, he means their quiet counsels, for men either deliberate and prepare for work while they sit, or they rise, and thus move and act.

He means, in short, that whether his enemies consulted silently and quietly, or attempted to do this or that, nothing was unknown to God.

Now, since God takes such notice of the counsels and all the actions of men, it must be that He restrains and checks the wicked, for God’s knowledge is always connected with His office as a judge.

Therefore, we see how the Prophet strengthens himself, as we have recently stated, and thus gathers a reason for confidence, for the wicked counsels of his enemies and their works were not hidden from God.

He adds, I am become a song. He again sets before God his reproach, cast upon him by the ungodly. For that indignity also served powerfully to move God not to allow His people to be treated unworthily.