Albert Barnes Commentary Lamentations 1:8

"Jerusalem hath grievously sinned; therefore she is become as an unclean thing; All that honored her despise her, because they have seen her nakedness: Yea, she sigheth, and turneth backward." — Lamentations 1:8 (ASV)

Grievously sinned - literally, Jerusalem hath sinned a sin, giving the idea of a persistent continuance in wickedness.

Removed - Or, become an abomination. Sin has made Jerusalem an object of horror, and therefore she is cast away.

Yea, she sigheth ... - Jerusalem groans over the infamy of her deeds thus brought to open shame, and turns her back upon the spectators in order to hide herself.