John Gill Commentary Psalms 109:29

"Let mine adversaries be clothed with dishonor, And let them cover themselves with their own shame as with a robe." — Psalms 109:29 (ASV)

Let mine adversaries be clothed with shame
This is only explanative of what is said before,

And let them cover themselves with their own confusion as with a
mantle :
the Arabic version is, "as with a breastplate." Some understand it as a petition of Christ, that they might be brought to repentance for their sins, and so to shame for them; which is an instance of his wondrous grace and goodness; and it is certain he prayed for the forgiveness of his enemies when on the cross, (Luke 23:34) .