The idea of eating and drinking here has nothing to do with salvation. Jesus had already mention that salvation is by faith alone in Christ read verse 47
You are correct that faith is required for salvation, but it is not faith alone that saves. If you query “faith alone” in any Bible search engine, the only verse that comes up is James 2:24, and it is stated in the negative. Jesus preaches that faith is needed, and He says it many times, but to say that He ever taught faith alone is sufficient for salvation is to ignore everything else that Christ taught.
Let’s take a starting point of faith. Isn’t faith sufficient for salvation? No.
One must repent (Lk 13:5)
One must forgive (Mt 18:35)
One must be humble (Mt 18:2-4)
One must live according to one’s faith (Mk. 4:14-20)
One must deny oneself and take up one’s own cross (Mk 8:34)
Please note that I am not arguing that doing good deeds or being a good person gets one into Heaven. We know from James that this is not so. What these commands amount to is that for those who believe, we must live in accordance with that belief, complete with its calls to repentence, holiness, worship, love, humility and charity.
So John’s stated purpose - a call to faith - is not just a call a faith, but to a loving, sincere, whole faith in Christ.
If communion or baptism were needed for salvation in addition to faith then John had a great opportunity to say so right here.
I hope you don’t hold it against the Evangelist that he said it elsewhere . One must be born again (Jn 3:3), and by born again Jesus clarifies to mean baptism (Jn 3:5). One must persevere in faith (Jn 15:3-5). And one must eat the Flesh and drink the Blood of Jesus (Jn 6:53).
Here you say that Jesus is speaking metaphorically, here I see He is speaking literally. Look at the structure of this passage: Jesus states a spiritual truth, those listening are confounded, and He reiterates His position. This is a common framework that we see elsewhere in John, ie when Jesus talks of being born again: He states it in Jn 3:3, Nicodemus rebutts what seems impossible in verse 4, Jesus restates it in verses 5-7. Likewise in Jn 6:38, Jesus states He came down from Heaven, the Jews rebutt what seems impossible in verse 42, Jesus restates it in verses 44-50. What confounds the listeners is not that it is a metaphor but that they don’t understand the spiritual truth that Jesus is speaking quite plainly.
Just as being born again is not a uterine transaction but rather a true new birth following the death of the old self (Rom 6:3-5), so is eating of the Body and Blood not about cannibalism of Jesus’ human body but the consuming of His Real Presence in the Body and Blood. There is no symbolism elsewhere in Scripture that pertains to eating of flesh and drinking of blood, except in the Last Supper, and I find it interesting that you chose to reference John to make your arguments because John is the sole Gospel without a Last Supper account. Thus to explain the significance of John 6, we must look to the other Gospel passages. Jesus explains the bread and the wine to be His Body and Blood, and that His Blood will be poured out for forgiveness of sins (Mt 26:26-28). He orders His disciples to do this in commemoration, but the Apostles did not just celebrate as mere rememberance.
Paul writes that taking the bread and the wine is participating in the Body and Blood of Christ (1 Cor 10:16). Not remembering, not symbolizing, but
participating. Paul, like Jesus, specifically admonishes his audience to believe elsewhere and in plain language, and like Jesus, speaks differently about the Body and Blood than about faith.
What ultimately confounds the argument that Jesus was using Flesh and Blood to refer to faith alone in John 6 is in 1 Cor 11:27-28. Paul writes that eating the Body and Blood in an “unworthy manner” brings guilt against the Body and Blood and admonishes us to examine our consciences before doing so. This is in context of a larger passage (verses 20 to 33) on how to partake in what he calls the Lord’s Supper. He admonishes them to physically eat and drink in community, to share, to remember, and to come with a clean conscience. How can one interpret this passage - this understanding of the Body and Blood - if the phrase means faith and nothing else? How can one have faith in an “unworthy manner” and thus bring guilt against faith itself?