What does John 6:48 mean?

This conversation began with Jesus correcting the false motives of the crowd. After seeing His miraculous feeding the day before, the people sought Jesus out in Capernaum. Christ immediately pointed out that their interest was not spiritual truth, but simply more free food (John 6:26). Rather, Jesus says, they ought to be pursuing "the food that endures to eternal life." When the people ask for this "Bread of Life," Jesus responds that this bread actually comes in the form of a person, sent by God (John 6:27–33). Those who believe in this person are guaranteed everlasting life (John 6:40). Jesus specifically points to Himself as that "Bread of Life," the first of seven uses of the divine "I AM" phrasing used in the gospel of John.

Here, Jesus again repeats this claim. In the verses just before this, He has pointed out that since He is the only one who came from heaven, He is the only one who can speak with firsthand knowledge about it. This is why Jesus uses the "truly, truly" phrasing in John 6:47, to emphasize the original, personal, absolute nature of His claims.

In the next verses, Jesus will give a deeper explanation for how the manna provided for Israel in the wilderness (Exodus 16) was only meant to be a foreshadowing of His own ministry.