With Passover basically just around the corner, this passage in 1 Corinthians is a perfect way to introduce the Feast of Passover, as it uses some great Passover imagery! (Not to mention, this chapter absolutely lays it on the line when it comes to sexual sin – which is just as prevalent today as it was in "biblical times.")
Take a look:
1 Corinthians 5:1. In short, it is reported, there is sexual sin among you; and such sexual sin as is not even named among the pagans, that a son should even take the wife of his father. 2. And you are puffed up, and have not rather sat down in grief, that he who has done this deed might be separated from you.
3. And I, while distant from you in body but present with you in spirit, have already, as if present, judged him who perpetrated this deed; 4. That all of you assemble together, in the name of our Master Y’shua Mashiyach, and I with you in spirit, together with the power of our Master Y’shua Mashiyach; 5. And that you deliver him over to Satan, for the destruction of the flesh, that in spirit he may have life, in the day of our Master Y’shua Mashiyach.
 And that “name” is the same as YHWH’s (John 17:11) and means “YHWH is salvation.” Once the basic understanding is in place of how all this comes from Him, it is acceptable to gather it all together and declare this affirmation of faith in YHWH and give thanks to His Son.
NOTE FROM CARMEN: Now here come the Passover references! Please pay special attention to them as they help to explain what Passover is all about.
1 Corinthians 5:6. Your bragging is not praiseworthy. Don’t you know, that a little leaven leavens the whole mass? 7. Purge out from you the old leaven, that you may be a new mass, as you are unleavened. For our Passover is the Mashiyach, who was slain for us.* 8. Therefore let us celebrate the festival, not with the old leaven, nor with the leaven of wickedness and bitterness, but with the leaven of purity and sanctity.
*NOTE FROM CARMEN: Please note the "Passover Lamb" was NOT a "sin offering!" The lamb for the original Passover was not even a sacrifice! The lamb was offered as a substitute, not as a "sacrifice." The "angel of death" passed over the believing Hebrews when the lamb's blood was on their door posts. So, though not a "sin" sacrifice, the lamb's blood was offered as a substitute, giving the Hebrew first-born males the chance to live. (For more on this, please see our website’s article, Was Yeshua the Passover Lamb?)
1 Corinthians 5:9. I wrote to you by letter, not to mingle with sexual sinners. 10. But I say not, with the sexual sinners who are in the world, nor (speak I) of the avaricious, or of the rapacious, or of the idol-worshippers, otherwise you would be obliged to go out of the world.
11. But this is what I wrote to you, that you don’t mix, if anyone is called a brother, and is a sexual sinner, or avaricious, or an idol-worshipper, or a charlatan, or a drunkard, or rapacious, with him who is such, not even to eat bread. 12. For what business have I to judge them who are without? But those within the body, judge you, 13. And those without, Elohim judges; and remove you the wickedness from among you. (Borrowed from the AENT)
 The word for “leaven” here is makhmae, the cognate in Hebrew of which is chometz. Therefore, Rav Shaul is teaching the Corinthians by using Passover imagery, by commanding them to purge the chometz from the house of their hearts, so that they can be sanctified. Of course, the rest of this verse and the next proves this interpretation.
 Breaking of bread, of course, is a timeworn Middle Eastern custom that is done only with family and friends. If you cannot eat with someone (as Peter tried to separate himself in Galatians 2:13), then you cannot associate with them at all.
If the sinner was out of the assembly, you were not permitted to persecute them. However, you could, and in fact you must, demand that such a person put away detestable habits if they are to join the assembly and partake of the communal and havdilah meals that Y’shua and his disciples enjoyed.