Although our Christian communion celebration came from Jesus' Last Supper, it was a normal Passover meal but with prophetic interpretation.  Jesus explained how His blood was symbolised in the cup of wine.  It was very personal: His body was broken, and His blood was shed, for all who will believe. Paul reminds the believers in Corinth that Christ’s body was broken for them, personally (1 Corinthians 11:24).

Many who are reading this do not have a Jewish background.  Those of us who are Gentiles, we need to remind ourselves that Jews down the ages celebrated (and still celebrate today) the Passover with four cups, rather than one. The first was the Cup of Sanctification - God's promise to bring them out of the land of sinfulness and make them a special people (Exodus 6:6).  The second was the Cup of Praise and Deliverance - God's promise to rescue His people.  The third was the Cup of Blessing and Redemption - God's promise to redeem His people from slavery.  And the fourth was the Cup of Completion - God's promise to finally gather His people to Himself (Galatians 3:13-14).  All four promises would be fulfilled by Jesus Christ.
 
This passage refers to what Jesus said when taking wine from the first or second cups; and also the fourth cup, after the meal.  It was His personal promise to rescue all those who believed in Him from the slavery of sin, and to complete the promise by gathering them to Himself on the Final Day (John 6:54).  Those promises were His new covenant which was to be sealed by His own blood (1 Corinthians 11:25).  They did not depend on people's ability to keep God's law (the old covenant), but on God's grace as the punishment for our sin was to be taken by Jesus (Ephesians 2:8-9).  When He broke the Passover bread in front of them, He said that it represented His body which was to be broken for them ... and that it was important that they remembered the cost of His sacrifice for them, and its sustaining power for those who live by faith in the Son of God (Galatians 2:20).
 
Unlike many pledges by human beings, God always keeps His promises.  The centuries of Passover celebrations recalled how God fulfilled His promise to deliver His people from physical slavery.  But the annual reminder was also always pointing forward to Jesus Christ - the only person who could complete God's plan of salvation.  The cross was to be the starting point: its completion will be in glory (2 Peter 3:13).  So, as we take bread and wine to remember the sacrifice of Christ, we look back to Calvary.  And we also look forward to His second coming when He will finally gather all those who love Him - out of this sin-sick world and into His presence for ever (Mark 13:26-27).  We should be very grateful for both events because we live in the tension between the two.  And it is also good to remember that His promises will never be broken; they will stand until every single one has been fully completed.