John Calvin Commentary John 6:64

"But there are some of you that believe not. For Jesus knew from the beginning who they were that believed not, and who it was that should betray him." — John 6:64 (ASV)

But there are some of you who do not believe. He again imputes blame to them because, lacking the Spirit, they wickedly corrupt and debase His doctrine, and thus turn it to their ruin. For otherwise they might have objected: “You boast, indeed, that what you speak is life-giving, but we experience nothing of that nature.” He therefore says that they themselves prevent this; for unbelief, as it is always proud, will never understand anything in the words of Christ which it despises and disdains.

Therefore, if we wish to benefit at all from this Teacher, let us bring minds well disposed to listen to Him. For if the entrance to His doctrine is not opened up by humility and reverence, our understandings are harder than stones and will not receive any part of sound doctrine.

Therefore, when today we see so few people in the world benefiting from the Gospel, we should remember that this arises from human depravity. For how many will you find who deny themselves and truly submit to Christ? As for His saying only that there were some who did not believe, even though almost all of them were subject to this charge, His reason for doing so appears to have been that, if there were any who were not yet beyond the possibility of cure, they might not become dejected in despair.

For Jesus knew from the beginning. The Evangelist added this so that no one would think that Christ formed an opinion at random about His hearers. Many professed to belong to His flock, but a sudden apostasy exposed their hypocrisy. But the Evangelist says that their treachery, even while it was unknown to others, was well known to Christ. And this is stated, not so much on His account, as that we may learn not to form a judgment except on subjects which we have thoroughly investigated. For as to their being known to Christ from the beginning, this was peculiar to His Divinity. It is different for us; for since we do not know hearts, we should delay forming a judgment until ungodliness is manifested by outward signs, and thus the tree be known by its fruits (Matthew 7:16).