Hereby we may understand that God, of His special grace, maketh the teachers of the gospel subject to the Cross, and to all kinds of afflicitons, for the salvation of themselves and of the people; for otherwise they could by no means beat down this beast which is called vain-glory.
Martin LutherPeter erred in life and in doctrine. Paul might have dismissed Peter's error as a matter of no consequence. But Paul saw that Peter's error would lead to the damage of the whole Church unless it were corrected. Therefore he withstood Peter to his face. The Church, Peter, the apostles, angels from heaven, are not to be heard unless they teach the genuine Word of God.
Martin LutherDoes it follow from: 'turn ye' that therefore you can turn? Does it follow from "'Love the Lord thy God with all thy heart' (Deut 6.5) that therefore you can love with all your heart? What do arguments of this kind prove, but the 'free-will' does not need the grace of God, but can do all things by its own power....But it does not follow from this that man is converted by his own power, nor do the words say so; they simply say: "if thou wilt turn,telling man what he should do. When he knows it, and sees that he cannot do it, he will ask whence he may find ability to do it..." 164
Martin Luther