You can't really say that A applies to B because they both use the word 'flesh', you have to read the text in context, for example in John 1:14 "And the Word was made flesh" which suggests, at the very least, the divinity of Jesus ...
The commentary on 6:63 He is saying that man's natural and carnal apprehension, (of the flesh (Gk sarx) as opposed to the body Gk soma) in refusing to be subject to the spirit and words of Christ, profits nothing thereby.
But if Christ's flesh had profited us nothing, he would never have taken flesh for us, nor died in the flesh for us, in the first place.
When He says "For my flesh is meat indeed: and my blood is drink indeed" (6:56) then He is making a distinction between Himself and other men.
Thomas
I'm not suggesting that the death, burial, and resurrection are not important in the physical evidence confirming coming Resurrection. Nor do I have any issues of the Word becoming flesh as evidence of Jesus' divinity. But if you are going to be consistent, be consistent in your context, Thomas. If 'flesh' in 6:63 means man's carnal nature, then it ought to be interpreted this way throughout the passage, as in 6:56. Which would then read thus: 'For my (carnal nature) is meat indeed...'. And I know you don't believe that is what's meant. The problem is that you are taking the whole passage too literally (except of course in 6:63). When you do that, you miss the point. I'll show you what I mean.
For example, back a couple of chapters in John 4:33, the disciples asked Jesus, 'Hath any man brought him ought to eat?' and Jesus replied, "My meat is to do the will of him that sent me, and to finish his work." It is obvious that Jesus isn't talking about real food, is He?
Now observe our text in John 6:27-29:
"Labour not for the meat which perisheth, but for that meat which endureth unto everlasting life, which the Son of man shall give unto you: for him hath God the Father sealed. Then said they unto him, What shall we do, that we might work the works of God? Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent."
Again, Jesus is not speaking of a literal physical food. How do we know that? Because of the disciple's reply, "What shall we do, that we might work the works of God?" The disciples reply echos the understanding of what Jesus said two chapters back, the work of God. And that work of God is to believe on Him whom God sent. It speaks nothing of the the Eucharest.
So in going back to 6:56, "For my flesh is meat indeed..." we now know that 'meat' means doing the will of God....via the Word of God.
Jesus in His temptation said,
"It is written, Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God." - Matthew 4:4
Where is it written? In Deuteronomy 8:3:
"And he humbled thee, and suffered thee to hunger, and fed thee with manna, which thou knewest not, neither did thy fathers know; that he might make thee know that man doth not live by bread only, but by every word that proceedeth out of the mouth of the LORD doth man live."
And isn't it interesting that manna is precisely the topic in John 6. Any Jew with knowledge of the Torah would connect what Jesus said in John 6:31-33 with Deut. 8:3.