Answer:
You refer to Jesus eating the Last Supper with His disciples, when He partook of the “cup,” containing the juice of the grape, and gave it to His disciples, and told them, “Drink from it, all of you” (Matt. 26:27). Then He proceeded to explain. His words are phrased slightly different in each of the Gospels, but they are in substance the same: that “This cup is the new covenant in my blood” (Luke 22:20; 1 Cor. 11:25). Or, “This is my blood of the new covenant” (Mark 14:24; Matt. 26:28).
We cannot read this passage without being impressed with its deep spiritual significance. Jesus was not talking about literal blood, because He was saying that the contents of the cup was “my blood”–when we know from the narrative that it was “the fruit of the vine,” i.e., grape juice, literally speaking. Jesus was speaking of the deep representative meaning of these symbols of the Passover. And Jesus Himself explains: that the “blood” is “the new testament,” the covenant of the believer with God, the obligation to obey, to offer one’s self a living sacrifice to God, as fully as Jesus Himself was doing at that point. If we interject any meaning of literal blood, we destroy the deep and beautiful truth that Christ was teaching His disciples, that the Passover was a rite they should perpetuate until such a time as He would partake of it “new in the kingdom of God” (Mark 14:25). “For as often as you eat this bread, and drink this cup, you proclaim the Lord’s death till He comes” (l Cor. 11:26).
Christ went out from the Passover to suffer physical death; but the real significance of that death lay in the fact that it was the end of His lifelong sacrifice, His last act in a life of perfect obedience. At the Passover He was bequeathing to His disciples the solemn obligation to make the same total surrender of themselves to God. If we take the cup as a cup of literal blood, we are making cannibals of the disciples instead of recognizing the deep spiritual lessons Christ was teaching.
In John 6, Jesus had said plainly, “Unless you eat the flesh of the Son of Man and drink His blood, you have no life in you” (v. 53). Then He went on to explain that it was not His literal flesh and blood at all, that “the flesh profits nothing. The words that I speak to you are spirit, and they are life” (John 6:63).
Jesus made the same sacrifice which each of His followers must make, pouring out His lifeblood in total submission to the will of His Father. This is the contents of the cup; this is the “new covenant in My blood, which is shed for you” (Luke 22:20). This was the blood to which Jesus referred when He said “This cup is the new covenant in my blood.”