64 Yet there are some of you who do not believe.” For Jesus had known from the beginning which of them did not believe and who would betray him.

Read John 6:64 Using Other Translations

But there are some of you that believe not. For Jesus knew from the beginning who they were that believed not, and who should betray him.
But there are some of you who do not believe." (For Jesus knew from the beginning who those were who did not believe, and who it was who would betray him.)
But some of you do not believe me.” (For Jesus knew from the beginning which ones didn’t believe, and he knew who would betray him.)