Jesus did use symbolic language:
Matthew 26:27-29 "(27) And he took the cup, and gave thanks, and gave it to them, saying, Drink ye all of it; (28) For this is my blood of the new testament, which is shed for many for the remission of sins. (29) But I say unto you, I will not drink henceforth of this fruit of the vine, until that day when I drink it new with you in my Father's kingdom." Jesus first refers to the content of the cup as "blood" but at the same time and in the same context Jesus calls the content "fruit of the vine". The content of the cup did not change for it was always fruit of the vine.
Also, in verse 27 the word "cup" is used figuratively for the content of the cup, therefore not literally drink the cup itself but drink the content of the cup.
"And he took the cup, and gave thanks, and gave it to them, saying, Drink ye all of it;"
Clearly a metonymy is being employed, a figure of speech where one thing (cup) stands for another (contents of cup). The "fruit of the vine" is literally the "it" which is also the cup itself.
Luke 22:17 "And he took the cup, and gave thanks, and said, Take this, and divide it among yourselves:" Again, a figure of speech is employed for "it" is not the literal cup itself that was to be divided but the content of the cup. (divide - diamerizō - to cleave asunder, cut in pieces; to be divided into opposing parts cf Matthew 27:35). Therefore the language of John 6:54 can and would be equally symbolic.
Also:
John 6:52 "The Jews therefore strove among themselves, saying, How can this man give us his flesh to eat?"
Those Jews strove for they incorrectly understood the words of Christ literally as did those disciples John 6:60. If those disciples understood what Christ said as literally eating Christ's flesh and murmured about it, Jesus points out as to what would they do when He physically left them ascending above, John 6:61-62.
So Christ's words are not referring to the literal, actual physical presence of Christ's blood or flesh. Luke 22:18-19 instructs disciples to take literal bread and fruit of the vine and "this do in remembrance of me". In "remebrance of Me" means Christ would not always have a physical flesh and blood presence among the disciples, hence no literal flesh and blood present for them to eat or drink. So what would those disciples do who took 'eat His flesh" literally when Christ physically left them ascending above?
Comparing two verses:
John 6:54 "Whoso eateth my flesh, and drinketh my blood, hath eternal life; and I will raise him up at the last day."
John 6:63 "It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they are life."
V54 says eating His flesh gives eternal life yet v63 says Christ's words give life. Hence Jesus "words" are equivalent to his eating & drinking His flesh and blood. Therefore eating flesh & drinking blood of v54 cannot be taken literally. After the misunderstanding of literally eating flesh by the Jews (v52) and disciples (vs 60-61) Christ puts back in perspective for them what is meant by eating flesh, that being, "eating flesh" (v54) = eating His "words" (v63) not literally eating His flesh.
Summary:
--John 6:32-33 Jesus is the "bread" God sent from heaven.
--John 6:35 those who continue to come to Christ (the Bread) shall never hunger and those that continue to believe shall never thirst. (to "drink Jesus" is to believe His word, not literally drink Jesus or His blood, John 7:37-38).
--John 6:37-40 explains verse 35, those who "see" and "believe" may have everlasting life (never hunger or thirst)
How do men come to Christ, the Bread?
--John 6:44-45 by being taught, hearing and learning gives everlasting life.
--John 6:48 thus Jesus is the true bread.
The context is not about the Lord's Supper but the need to accept Jesus as the Bread God sent to the world, to "eat and drink" Him, that is, not literally eat and drink His flesh and blood but to believe His words to have eternal life. The whole context starts with v27 when Jesus tells them to work for the "meat" that endures unto everlasting life. Working for this "meat" refers to believing the words of Christ that He gives men and not literal meat to eat, not His literal flesh and blood to eat.
Final comment on John 6:54:
"Whoso eateth my flesh, and drinketh my blood, hath eternal life; and I will raise him up at the last day."
The verbs 'eateth' and 'drinketh' are present tense verbs denoting an action occuring in real time on a continuing basis meaning Christ's disciples were to be "eating" flesh and "drinking" His blood at that moment in real time and continue to eat and drink His flesh and blood. But the disciples were not literally eating His flesh and blood at that time nor did they literally continue in a process to eat His flesh.
Again, as noted already, the "eating" and "drinking" results in having eternal life. Christ's "words" also results in life, verse 63. Therefore eating His flesh (figurative) is eqivalent to taking in, receiving His words (literal).
Those who continue to receive His words have life, it's NOT continue to literally eat His flesh have life.
John 6:56 those who eat Christ's flesh results in Christ abiding in them and they abiding in Christ. Parallel verse to John 6:56 is 1 John 3:24 where keeping Christ's commands likewise results in one abiding in Christ and Christ abiding in him just as in John 6:56.
Hence eating Christ's flesh is symbolic and equivalent to literally keeping Christ's commands (words).
