Charles Ellicott Commentary Lamentations 2:3

"He hath cut off in fierce anger all the horn of Israel; He hath drawn back his right hand from before the enemy: And he hath burned up Jacob like a flaming fire, which devoureth round about." — Lamentations 2:3 (ASV)

All the horn of Israel ... —The horn, as elsewhere (1 Samuel 2:1; Psalms 92:10; Psalms 112:9), is the symbol of strength, aggressive or defensive, and may therefore stand here for every element of strength, warriors, rulers, fortresses.

He burned against Jacob. —Better, And He kindled a burning; i.e., was as one who applies the torch.