Therefore let us keep the feast, not with the old bread, leavened with malice and wickedness, but with the unleavened bread of sincerity and of truth.
KJV
Therefore 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.
ASV
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.
Paul says: I did not mean the people of the world who do wrong, or want too much, or cheat, or pray to fake gods. If so, you all would have to leave the world.
I was not including the sexually immoral of this world, or the greedy and swindlers, or idolaters. In that case you would have to leave this world.
KJV
Yet not altogether with the fornicators of this world, or with the covetous, or extortioners, or with idolaters; for then must ye needs go out of the world.
ASV
not at all meaning with the fornicators of this world, or with the covetous and extortioners, or with idolaters; for then must ye needs go out of the world: