26While they were eating, Jesus took some bread, and after a blessing, He broke it and gave it to the disciples, and said, “Take, eat; this is My body.†27And when He had taken a cup and given thanks, He gave it to them, saying, “Drink from it, all of you; 28for this is My blood of the covenant, which is poured out for many for forgiveness of sins. 29“But I say to you, I will not drink of this fruit of the vine from now on until that day when I drink it new with you in My Father’s kingdom.â€
Matthew 26:26-29
22While they were eating, He took some bread, and after a blessing He broke it, and gave it to them, and said, “Take it; this is My body.†23And when He had taken a cup and given thanks, He gave it to them, and they all drank from it. 24And He said to them, “This is My blood of the covenant, which is poured out for many. 25“Truly I say to you, I will never again drink of the fruit of the vine until that day when I drink it new in the kingdom of God.â€
Mark 14:22-25 NASB
14When the hour had come, He reclined at the table, and the apostles with Him. 15And He said to them, “I have earnestly desired to eat this Passover with you before I suffer; 16for I say to you, I shall never again eat it until it is fulfilled in the kingdom of God.†17And when He had taken a cup and given thanks, He said, “Take this and share it among yourselves; 18for I say to you, I will not drink of the fruit of the vine from now on until the kingdom of God comes.†19And when He had taken some bread and given thanks, He broke it and gave it to them, saying, “This is My body which is given for you; do this in remembrance of Me.†20And in the same way He took the cup after they had eaten, saying, “This cup which is poured out for you is the new covenant in My blood.
Luke 22:14-20 NASB
52Then the Jews began to argue with one another, saying, “How can this man give us His flesh to eat?†53So Jesus said to them, “Truly, truly, I say to you, unless you eat the flesh of the Son of Man and drink His blood, you have no life in yourselves. 54“He who eats My flesh and drinks My blood has eternal life, and I will raise him up on the last day. 55“For My flesh is true food, and My blood is true drink. 56“He who eats My flesh and drinks My blood abides in Me, and I in him. 57“As the living Father sent Me, and I live because of the Father, so he who eats Me, he also will live because of Me. 58“This is the bread which came down out of heaven; not as the fathers ate and died; he who eats this bread will live forever.â€
John 6:52-58
14Therefore, my beloved, flee from idolatry. 15I speak as to wise men; you judge what I say. 16Is not the cup of blessing which we bless a sharing in the blood of Christ? Is not the bread which we break a sharing in the body of Christ? 17Since there is one bread, we who are many are one body; for we all partake of the one bread.
1 Corinthians 10:14-17 NASB
23For I received from the Lord that which I also delivered to you, that the Lord Jesus in the night in which He was betrayed took bread; 24and when He had given thanks, He broke it and said, “This is My body, which is for you; do this in remembrance of Me.†25In the same way He took the cup also after supper, saying, “This cup is the new covenant in My blood; do this, as often as you drink it, in remembrance of Me.†26For as often as you eat this bread and drink the cup, you proclaim the Lord’s death until He comes.
1 Corinthians 11:23-26 NASB
The observant reader will note the context of each account regarding the Lord's Supper.
In Matthew, Mark and Luke Jesus is addressing the disciples. In John He is addressing disbelieving Jews.
When all accounts of the Lord's instructions are taken into account one sees the clear meaning of the text. The bread and wine are symbolic of His flesh and blood. Paul's instructions he received from our Lord make this clear.
When we participate in the Lord's Supper, or Eucharist, we are remembering the sacrifice He made for us and we are identifying as a believer in Christ.
Again, context is key to understanding the Word.
Context also tells us that eating of blood is forbidden by God and that since Jesus came to fulfill the Law and not break or abolish it, then the restriction on eating blood was still in effect during the Last Supper, therefore Jesus could not have given the disciples blood to drink, and being observant Jews, they would have refused to do so if they thought it were actual, real blood.