Thomas Aquinas Commentary Lamentations 3:43-45

"Thou hast covered with anger and pursued us; thou hast slain, thou hast not pitied. Thou hast covered thyself with a cloud, so that no prayer can pass through. Thou hast made us an off-scouring and refuse in the midst of the peoples." — Lamentations 3:43-45 (ASV)

1. You have struck us by various tribulations, and then finally you have killed. Because the jealousy and rage of the husband will not spare in the day of revenge (Proverbs 6:34).
2. By rejecting the prayer of sinners, you have set a cloud before you—that is, our sins—placing them as a barrier to our prayer. But your iniquities have divided between you and your God (Isaiah 59:2).
3. By dispersing them, you have made them an outcast, torn, as it were, from the constancy of your protection and filled with your indignation. Through the force of winds they shall be rooted out. For the branches not being perfect, shall be broken .