This happened after the Jews complained about him, because he said that he was the bread that came down from heaven (John 6:35-40)
John 6:41 - 58
NKJV - 41 The Jews then complained about Him, because He said, "I am the bread which came down from heaven. 42 And they said, "Is not this Jesus, the son of Joseph, whose father and mother we know? How is it then that He says, 'I have come down from heaven' ?
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I always thought that it simply meant that we have to absorb His Spirit.
Stanford Ross