First of all, Passover was a type. While it recalled Israel's deliverance from bondage in Egypt (a type of sin), it pictured the coming of the One who would deliver man from bondage to sin by His own blood. Second, Jesus was an observant Jew observing every aspect of the law. Third, on the final Passover He was demonstrating that He was the fulfillment of the Passover. Today, we celebrate the fulfillment of the Passover when we celebrate Communion ... which God says we should do "as often as you meet". I would be so bold as to suggest that Communion IS our Passover.