Albert Barnes Commentary 1 Corinthians 5:8

"wherefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth." — 1 Corinthians 5:8 (ASV)

Let us keep the feast. The margin note is Holy day—eortazwmen. This is language drawn from the paschal feast and is used by Paul frequently to elaborate on and apply his illustration. It does not literally mean the paschal supper here—for that had ceased to be observed by Christians—nor the Lord's Supper particularly. But the sense is this: "As the Jews, when they celebrated the paschal supper on the slaying and sacrifice of the paschal lamb, put away all leaven as emblematic of sin, so let us, in the slaying of our sacrifice, and in all the duties, institutions, and events resulting from it, put away all wickedness from our hearts as individuals, and from our societies and churches. Let us engage in the service of God by putting away all evil."

Not with old leaven. Not under the influence or in the indulgence of the feelings of corrupt and unrenewed human nature. The word leaven is very expressive of that former or old condition, and denotes the corrupt and corrupting passions of our nature before it is renewed.

The leaven of malice. Of unkindness and evil—which would spread and invade the body of Christians. The word malice—kakia—denotes evil in general.

And wickedness. Sin; evil. There is a particular reference here to the case of the incestuous person. Paul means that all wickedness should be put away from those who had been saved by the sacrifice of Christ, their Passover; and therefore, this sin in particular.

But with the unleavened bread, etc. That is, with sincerity and truth. Let us be sincere, true, and faithful; just as the Jews partook of unleavened bread, which was emblematic of purity, so let us be sincere and true. It is implied here that this could not be done unless they put away the incestuous person. No Christians can demonstrate sincerity who are not willing to put away all sin.