Musar zu Ejchah 3:39

But now consider that even in the quality of worry there is some good to be found, as the Prophet said, "Wherefore doth a living man complain — A strong man because of his sins?" (Lam. 3:29). The sinner should nurture sadness in his heart and grieve in the bitterness of his heart that he has rebelled against the Creator of all.