1 Cor. 5:7-8 (ESV)
Cleanse out the old leaven that you may be a new lump, as you really are unleavened. For Christ, our Passover lamb, has been sacrificed. Let us therefore celebrate the festival, not with the old leaven, the leaven of malice and evil, but with the unleavened bread of sincerity and truth.
Christ is our Passover Lamb, and He has been sacrificed. The Passover was always celebrated once a year. The Israelites would gather together, sacrifice a lamb and eat it, all of it. This meant that families would get together to celebrate the Passover. A lamb is just too much food for one person to eat. The Passover was to be celebrated with family. It was a joyous occasion remembering how Israel was saved from bondage to Egypt, and how God prepared the people for their long trek through the desert to the Red Sea, by feeding them Lamb the night before.
Christ is our Passover Lamb, and He has been sacrificed. Now all there is to do is to eat Him, for the Passover Lamb is to be eaten. There was no benefit to the sacrifice if it was not consumed. We consume our Passover Lamb at Holy Communion. It is a joyous occasion. Forgiving our sins, it frees us from bondage to sin, death, and the power of the Devil. It feeds us and nourishes us, preparing us for our journey through the desert of this world. So we celebrate not by eating the old leavened bread of Egypt, the malice and evil. It is to joyous an occasion to be tainted with selfishness, violence and hatred. Rather, we eat the unleavened bread of sincerity and truth, in Christ Jesus our Lord, and celebrate with love.