“So Jesus said to them, ‘Truly, truly, I say to you, unless you eat the flesh (τὴν σάρκα) of the Son of man and drink his blood, you have no life in you; he who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day. For my flesh is food indeed, and my blood is drink indeed… This he said in the synagogue, as he taught at Capernaum. Many of his disciples, when they heard it, said, ‘This is a hard saying; who can listen to it?’” (Jn 6: 53-55, 59-60)
All this occurs well before Holy Thursday, when the Lord at His Supper commanded us to eat a certain bread as His “body,“ and to drink a certain cup as His “blood.“ There is no way that already here, in John 6, anyone could have understood these shocking words about “eating His flesh“ and “drinking His blood.“ So it’s not surprising that “after this, many of his disciples drew back and no longer went about with him” (Jn 6: 66). What is surprising, I think, is that any of them stayed, specifically, the twelve, – even though they, too, did not understand these words.
Why did they stay? Because they “believed” or “trusted” Christ, Whom they had “come to know” as the One Source of Life, even while they did not “understand” a lot of what He was saying and doing. When Jesus asked them, toward the end of John 6, “Do you also wish to go away?” Peter responded for all of them, saying, “Lord, to whom shall we go? You have the words of eternal life, and we have believed, and have come to know, that you are the Holy One of God” (Jn 6: 67-69).
Having “faith” (or “πίστις” in the Greek, which is best rendered as “trust”) in someone does not mean “understanding” them, in the sense of “figuring (them) out,” which would mean “mastering” them as we might an academic subject. “Trust” plays no role where there is no element of the unknown; where there is no mystery. But “trust” comes into play when we have come to “know enough” (but not everything) about another, to stick things out with him/her, also amidst his/her “mysterious” moments. Our Lord Jesus Christ, by calling us to Himself as He does, sometimes with “mysterious” words and actions, is teaching us to allow for the “mystery” in our most important relationships, with God and other loved ones. We are not to “master” them, like an academic subject, but to “trust” them, when we “know enough” about them to merit that, just as we want to be “trusted” but not “mastered.” Thank You, Lord, for teaching us to respect the freedom of others, and to be free, in our loves.