The Lord's Supper is the end of Passover. It is its fulfillment, its purpose, its τέλειος. On the night Jesus was being betrayed, the final Passover they ate together became the Lord's Supper as the New Covenant was established.

Judas' betrayal of Christ for 30 pieces of silver marked the transition from the Old to the New Covenant, as he ate the Passover as a Jew, but didn't stay for the whole Supper. In the Lord's Supper, we no longer only see the shadows of a lamb whose slaughter never took a single sin away from the families who brought it to Passover, but now remember the substance of the Lamb who took away the sins of the world.