Leavened vs. Unleavened Bread in the Eucharist

1 Cor 5

6-8

Your boasting is not appropriate. Do you not know that a little yeast leavens all the dough? Clear out the old yeast, so that you may become a fresh batch of dough, inasmuch as you are unleavened. For our paschal lamb, Christ, has been sacrificed. Therefore let us celebrate the feast, not with the old yeast, the yeast of malice and wickedness, but with the unleavened bread of sincerity and truth.