Communion/Eucharist is described in verses already quoted here but I will post then once again. (NKJV) I'll put Paul's comments first since he wrote before the Gospels were written.
1Co 11:23-28 For I received from the Lord that which I also delivered to you: that the Lord Jesus on the same night in which He was betrayed took bread; and when He had given thanks, He broke it and said, “Take, eat;fn this is My body which is broken for you; do this in remembrance of Me.” In the same manner He also took the cup after supper, saying, “This cup is the new covenant in My blood. This do, as often as you drink it, in remembrance of Me.” For as often as you eat this bread and drink this cup, you proclaim the Lord’s death till He comes.
Mat 26:26-28 And as they were eating, Jesus took bread, blessed and broke it, and gave it to the disciples and said, “Take, eat; this is My body.” Then He took the cup, and gave thanks, and gave it to them, saying, “Drink from it, all of you. “For this is My blood of the new covenant, which is shed for many for the remission of sins.
Mar 14:22 And as they were eating, Jesus took bread, blessed and broke it, and gave it to them and said, “Take, eat; this is My body.” Then He took the cup, and when He had given thanks He gave it to them, and they all drank from it. And He said to them, “This is My blood of the new covenant, which is shed for many."
Luke 22:19-20 And He took bread, gave thanks and broke it, and gave it to them, saying, “This is My body which is given for you; do this in remembrance of Me.” Likewise He also took the cup after supper, saying, “This cup is the new covenant in My blood, which is shed for you.
Often neglected in discussions of communion/Eucharist are Jesus' words in John's Gospel which expand the understanding of the bread/body, wind/blood teaching. Remember, John's Gospel was written well after the other three Gospels. Perhaps he saw a need for further instruction on communion/Eucharist.
John 6:48-60 I am the bread of life. Your fathers ate the manna in the wilderness, and are dead. This is the bread which comes down from heaven, that one may eat of it and not die. I am the living bread which came down from heaven. If anyone eats of this bread, he will live forever; and the bread that I shall give is My flesh, which I shall give for the life of the world.”
The Jews therefore quarreled among themselves, saying, “How can this Man give us His flesh to eat?”
Then Jesus said to them, “Most assuredly, I say to you, unless you eat the flesh of the Son of Man and drink His blood, you have no life in you. Whoever eats My flesh and drinks My blood has eternal life, and I will raise him up at the last day. For My flesh is food indeed,fn and My blood is drink indeed. He who eats My flesh and drinks My blood abides in Me, and I in him. As the living Father sent Me, and I live because of the Father, so he who feeds on Me will live because of Me. This is the bread which came down from heaven—not as your fathers ate the manna, and are dead. He who eats this bread will live forever.”
These things He said in the synagogue as He taught in Capernaum. Therefore many of His disciples, when they heard this, said, “This is a hard saying; who can understand it?”
John 6:66-68 From that time many of His disciples went back and walked with Him no more. Then Jesus said to the twelve, “Do you also want to go away?”
But Simon Peter answered Him, “Lord, to whom shall we go? You have the words of eternal life."
The passage in John has been hard to accept from the day that Jesus spoke the words. Many of His disciples left Him after hearing those words. It seems clear to me that Jesus was talking about the bread and wine of communion/Eucharist for how else could we "eat" His flesh and "drink" His blood except by participation in communion/Eucharist?
That is how the earliest leaders of the church understood Communion as is attested in their writings.
Ignatius of Antioch (30-107 A. D. A disciple of the apostle John and Bishop of Antioch) in his Epistle to the Smyrnaens, Ch. VII: “Let Us Stand Aloof from Such Heretics” states; “They (the heretics) abstain from the Eucharist and from prayer, because they confess not the Eucharist to be the flesh of our Saviour Jesus Christ, which suffered for our sins,..”
He was taught by the John, the beloved disciple of Christ and, in this statement, he affirms the teaching of the apostles and Christ that the bread is Christ’s body.
Justin Martyr, the church’s first apologist, wrote in the first half of the 2nd century in his “The First Apology of Justin”, in Chapter LXVI.—Of the Eucharist. In it he reports what he was taught as a new Christian by the church. That would mean that the teaching he received was already established in the church so it is not some later invention by the Roman church but was a part of the teaching of the apostles who taught what they learned from Jesus. It is God’s inspired teaching by His Son, through the apostles to the church.
And here it is: “And this food is called among us Eujcaristiva [the Eucharist], of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined. For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Saviour, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh. For the apostles, in the memoirs composed by them, which are called Gospels, have thus delivered unto us what was enjoined upon them; that Jesus took bread, and when He had given thanks, said, “This do ye in remembrance of Me, this is My body; ”and that, after the same manner, having taken the cup and given thanks, He said, “This is My blood; ”and gave it to them alone.”
So, we probably shouldn't consider sitting around the kitchen table having PB&J sandwiches and a glass of milk to be "Communion."
At least, that's how I see it.
Iakov the fool