Theophylact of Bulgaria
"This we will do." What is this? It is to go on to perfection, if God wills. He did not say this as though God did not command it. Rather, he spoke in the usual way, saying that if it is pleasing to God, this is what he himself wishes to do. At the same time he teaches us here to place everything in dependence on His will. Even in unquestionably good works, we must not trust our own judgment and powers. The Apostle Jude also clearly persuades us of this.