5:1-8 The apostle notices a flagrant abuse, winked at by the Corinthians. Party spirit, and a false notion of Christian liberty, seem to have saved the offender from censure. Grievous indeed is it that crimes should sometimes be committed by professors of the gospel, of which even heathens would be ashamed. Spiritual pride and false doctrines tend to bring in, and to spread such scandals. How dreadful the effects of sin! The devil reigns where Christ does not. And a man is in his kingdom, and under his power, when not in Christ. The bad example of a man of influence is very mischievous; it spreads far and wide. Corrupt principles and examples, if not corrected, would hurt the whole church. Believers must have new hearts, and lead new lives. Their common conversation and religious deeds must be holy. So far is the sacrifice of Christ our Passover for us, from rendering personal and public holiness unnecessary, that it furnishes powerful reasons and motives for it. Without holiness we can neither live by faith in him, nor join in his ordinances with comfort and profit.

8. not … old leaven—of our unconverted state as Jews or heathen.

malice—the opposite of "sincerity," which allows no leaven of evil to be mixed up with good (Mt 16:6).

wickedness—the opposite of "truth," which allows not evil to be mistaken for good. The Greek for "malice" means the evil habit of mind; "wickedness," the outcoming of the same in word and deed. The Greek for "sincerity" expresses literally, a thing which, when examined by the sun's light, is found pure and unadulterated.