Albert Barnes Commentary Lamentations 3:43

"Thou hast covered with anger and pursued us; thou hast slain, thou hast not pitied." — Lamentations 3:43 (ASV)

In verses 43-66, far from pardoning, God is still actively punishing His people.

Rather, You have covered Yourself with wrath and pursued (see note on Lamentations 1:3) us. The covering (here and in Lamentations 3:44) is that of clothing and enwrapping.