It is disappointing to find some well-meaning brethren calling the Lord’s Supper the Passover.
Surely Luke 22:14-20 proves conclusively that after the observance of the Passover, our Lord instituted a “remembrance” of His death.
When Paul recounts what our Lord did and said at the Lord’s Supper he mentions only bread and wine, while at the Passover there was certainly much more than this.
The Passover, like water baptism, was an Old Testament ordinance, but the Lord’s Supper is as distinctly associated with the New Testament, or Covenant.
“For this is My blood of the New Testament…” (Matt. 26:28).
The Passover, like water baptism, spoke of an unfinished work, for if water cannot wash away sin, neither can the blood of bulls and goats take away sins (Heb.10:4). Both were shadows of the redeeming work of Christ.
Because so many stumble over the fact that water baptism was practiced even after the cross, we repeat that the full results of Calvary were not manifested until “due time,” through the Apostle Paul. Blood sacrifices, circumcision, the sabbaths and feast days likewise spoke of an unfinished work, yet these were all observed after the cross — by the Spirit-filled disciples. This is simply because the time for the unfolding of God’s secret purpose and the gospel of the grace of God was not ripe until God raised up that other apostle, Paul. Indeed, even then its unfolding and the passing away of the old order were gradual matters.
BUT— whereas the Passover and water baptism were Old Testament ordinances, the Lord’s Supper is distinctly a New Testament celebration. The celebration of the Lord’s death should never be classed with the ordinances, not even with the ordinance of baptism, for while water baptism spoke of an unfinished work, the Lord’s Supper is clearly a celebration of the finished work of Christ.
At least three times the Lord’s Supper is stated to be “in remembrance” of Christ and His redemptive work. source