Make you perfect (katartisai). First aorist active optative of katartizō, to equip, as in Heb 10:5. A wish for the future. See 1Co 1:10; 2Co 13:11; 2Ti 3:17.
Working in us (poiōn en hemin). “Doing in us.” Some MSS. read “in you.”
Well-pleasing (euareston). Compound adjective (eu, arestos). Usually with the dative (Rom 12:2), here with enōpion autou more like the Hebrew. This is one of the noblest doxologies in the N.T.