because He knew they would refuse to believe Him regarding His teaching of His body and blood, among other things.
True...but Jesus was no more being literal there than he was in John 4:
“13Jesus said to her, “Everyone who drinks of this water will be thirsty again, 14but whoever drinks of the water that I will give him will never be thirsty again. The water that I will give him will become in him a spring of water welling up to eternal life.” 15The woman said to him, “Sir, give me this water, so that I will not be thirsty or have to come here to draw water.”
John 5:
“35He was a burning and shining lamp, and you were willing to rejoice for a while in his light. 36But the testimony that I have is greater than that of John.”
John 7:
“38Whoever believes in me, as the Scripture has said, ‘Out of his heart will flow rivers of living water.’” 39Now this he said about the Spirit, whom those who believed in him were to receive, for as yet the Spirit had not been given, because Jesus was not yet glorified.”
Jesus didn’t give the woman at the well superwater. John the Baptist wasn’t a flashlight. And Christians aren’t water fountains.
And earlier in chapter 6 we read: “35Jesus said to them, “I am the bread of life; whoever comes to me shall not hunger, and whoever believes in me shall never thirst.”
All of these verses have spiritual meaning. As is, “48 I am the bread of life. 49 Your fathers ate the manna in the wilderness, and they died. 50 This is the bread that comes down from heaven, so that one may eat of it and not die. 51I am the living bread that came down from heaven. If anyone eats of this bread, he will live forever. And the bread that I will give for the life of the world is my flesh.”