The LORD will perfect that which concerns me: your mercy, O LORD, endures forever: forsake not the works of your own hands.
Read Chapter 138
Augustine of Hippo
12. "Thou, Lord, shalt recompense for me" (ver. 8). I recompense not: Thou shalt recompense. Let mine enemies rage their full: Thou shall recompense what I cannot. ..."Dearly beloved, avenge not yourselves," saith the Apostle, "but rather give place unto wrath; for it is written, Vengeance is Mine, I will repay, saith the Lord." There is here another sense not to be neglected, perhaps even to be preferred. "Lord" Christ, "Thou shall repay for me." For I, if I repay, have seized; Thou hast paid what Thou hast not seized. Lord, Thou shall "repay for me." Behold Him repaying for us. They came to Him, who exacted tribute: they used to demand as tribute a didrachma, that is, two drachmas for one man; they came to the Lord to pay tribute; or rather, not to Him, but to His disciples, and they said to them, "Doth not your Master pay tribute?" They came and told Him. He saith unto Peter, "lest we should offend them, go thou to the sea, and cast an hook, and take up the fish that first cometh up...
Repay. Taking me under his protection, (St. Chrysostom) he will punish my oppressors; or he has done it already. (Calmet)
Hands. Rescue me from the oppression of my temporal and spiritual enemies. (Berthier)