It means that without the Holy Spirit, we are lost, and that human nature unaided by grace can do nothing.
“Without me, you can do nothing.”
The “flesh” in the sense of unaided human nature is NOT the flesh of Jesus which he promises to give us to eat. I have seen these words twisted, as though Jesus is saying “MY flesh profiteth nothing.” (And, therefore, what’s the point of giving us his flesh to eat?)
It’s amazing how people will twist themselves into pretzels trying to prove that, in John 6, Jesus isn’t saying anything more interesting than “have faith.” And saying it VERY BADLY.
The Holy spirit hadn't even been mentioned...In the entire Chapter...The Holy Spirit hadn't even shown up yet...