At the Passover celebration Jesus started the communion celebration.  He used the Bread (unleavened) to represent His Body and the Wine to represent the His Blood.

The Passover was commissioned when God set the Israelites free from slavery from the Egyptians.  They were to sprinkle the blood on the post of the doors to their homes and they were to eat the lamb which blood had been shed together with the unleavened bread.  This was a feast or festival they did annually in remembrance of the great deliverance from the Egyptians.

At one of such feast or festival Jesus started the celebration known today has Holy communion or Holy Eucharist.  He took bread, broke it and gave it to His disciples telling them do this in remembrance of Him.  Likewise He took the cup which had the wine gave it to His disciples, telling them to do this as often in remembrance of Him.  

That event was a fulfilment of the Passover.  Christ is the ultimate Lamb that was sacrificed.  Because of His sacrifice we no longer have to perform the Passover.

The sprinkling of blood on the door post was a covering for the inhabitants of the household. However the shedding of Christ blood is not a covering but a cleansing.  

When we get baptised by water, we are immersed in the water symbolising our being buried with Christ.  When we arise out of the water we are being raised with Christ into a new life.  The old has passed away all things have become new.

Christ died that we might live and live eternally.  Passover was a covering until the promise of Genesis was fulfilled.  That promise is fulfilled at the final Passover when Christ instituted the celebration of communion.  We have to constantly remember this so we can live in the victory that is ours in Christ.

This is why we celebrate Communion.  To remind us of the perfect and ultimate sacrifice.  Our sins are no longer covered but washed away.  We are fit to enter God's presence.  

Amen.