Albert Barnes Commentary Lamentations 1:9

"Her filthiness was in her skirts; she remembered not her latter end; Therefore is she come down wonderfully; she hath no comforter: Behold, O Jehovah, my affliction; for the enemy hath magnified himself." — Lamentations 1:9 (ASV)

Her filthiness is in her skirts — Her personal defilement is no longer concealed beneath the garments (Jeremiah 13:22).

She came down wonderfully — Jerusalem, once enthroned as a princess, must sit on the ground as a slave.