What does John 6:68 mean?

Verses 68 and 69 are Peter's witness to Jesus' divinity; this is the third of seven such declarations in the gospel of John. Peter's response comes after most of Jesus' followers turn and walk away. Because His recent teachings are challenging (John 6:60), the crowd proves their lack of actual faith by completely abandoning Jesus and His ministry. Their reaction is not merely described as "leaving," but implies that they totally dismissed His spiritual truth (John 6:66).

None of the disciples fully understand what Jesus' symbolic teaching about bread, flesh, and blood really means. That understanding won't be complete until after Christ' resurrection (John 20:9). And yet, Peter's response is exactly how a believer responds when Christ disrupts their preferences, their traditions, or their personal opinions. Here, Peter's response is extremely practical and very logical: "where else are we going to go, since only you have the truth?" When faced with a choice between what we like, and what is true, we ought to stick with truth, even if it's uncomfortable.