Albert Barnes Commentary Psalms 109:23

"I am gone like the shadow when it declineth: I am tossed up and down as the locust." — Psalms 109:23 (ASV)

I am gone like the shadow when it declineth - See the notes at (Psalms 102:11).

I am tossed up and down as the locust - Agitated, moved, driven about, as a cloud of locusts is by the wind. The meaning of the whole is, that he was frail and weak, and needed strength from on high.