How is it possible that a Christian church, some 25 years after the ascension of Christ, was still observing the oldest known Jewish holiday? And they were. It is easily demonstrated. And they weren’t even a Jewish church. This one was mostly Gentile.
Paul wrote to the church in Corinth in about AD 55, and scholars generally agree that the letter was written about Passover season. He was addressing a problem that was disgracing the church, and almost in passing—as though he took it for granted—he made a remark about the Passover that is somewhat startling.
Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump? 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.
Now, how is the connection made here to the Passover, and why was this church observing it, and why was Paul advocating it?