Although I am a doctor of divinity, and have preached Christ and fought His battles for a long time, I know from personal experience how difficult it is to hold fast to the truth. I cannot always shake off Satan. I cannot always apprehend Christ as the Scriptures portray Him. Sometimes the devil distorts Christ to my vision. But thanks be to God, who keeps us in His Word, in faith, and in prayer.
The spiritual witchery of the devil creates in the heart a wrong idea of Christ. Those who share the opinion that a person is justified by the works of the Law, are simply bewitched. Their belief goes against faith and Christ.
Martin Luther: Commentary on the Epistle to the Galatians (1535)
Trans. Theodore Graebner