Caravaggio, Saint Jerome Writing (c. 1605), Galleria Borghese. Public domain.
2 verses in the King James Version. Word study for “old” →
Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even Christ our passover is sacrificed for us:
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.