Kehillah in Corinth I 5:7-9

Orthodox Jewish Bible

⁷ Purge out the old chametz (leavened bread), that you may be issa chadasha (new dough, batzek, deaf dough, having no indication of fermentation), as you are indeed like matzot (unleavened bread). More than that, our Korban Pesach has been sacrificed, Moshiach. [SHEMOT 12:3-6,21]

⁸ So let us celebrate Pesach, not with old chametz, nor with the chametz of kavvanah ra’ah (malice) and wickedness, but with matzot of kenut (sincerity) and emes. [SHEMOT 12:14,15; DEVARIM 16:3]

⁹ I wrote to you in the iggeret not to mix with those engaging in acts of zenut (fornication),