Read the scripture a little before what you have posted.
John 6:63-64 The Spirit gives life; the flesh counts for nothing. The words I have spoken to you are spirit and they are life.
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.
So JLB, the above was spoken from Jesus's mouth. Jesus knows the heart of a person and knew Judas did not believe, even though he chose him.
Yes, there were some of His disciples who stopped believing, which is prefaced by the fact that
they no longer walked with Him anymore.
From that
time many of His disciples
went back and walked with Him no more. Then Jesus said to the twelve,
“Do you also want to go away?”
Those who stopped believing, stopped following,
as they stopped being "His disciples", prefaced by the fact that they
"stopped following"
This was not so, of
the twelve, because they
continued following Jesus, and were still "His disciples" at this point.
A disciple is someone who follows their teacher and learns from Him. A disciplined follower.
Peter representing the twelve said these words, when asked:
“Do you also want to go away?”
But Simon Peter answered Him, “Lord, to whom shall we go? You have the words of eternal life. 69 Also
we have come to believe and know that You are the Christ, the Son of the living God.”
Those who believed; followed.
Those who no longer believe; no longer followed, as they were no longer disciples.
Did Judas turn away from following Jesus, with the rest of those who didn't believe anymore?
There were those who didn't believe, as they stopped following, and there was Judas who betrayed Him.
- Judas was not among those who didn't believe.
- Those who didn't believe were not counted as the one who betrayed Him
60 Therefore many of His disciples, when they heard
this, said, “This is a hard saying; who can understand it?”
61 When Jesus knew in Himself that His disciples complained about this, He said to them, “Does this offend you? 62
What then if you should see the Son of Man ascend where He was before? 63 It is the Spirit who gives life; the flesh profits nothing. The words that I speak to you are spirit, and
they are life. 64 But there are some of you who do not believe.”
For Jesus knew from the beginning who they were who did not believe, and who would betray Him. 65 And He said, “Therefore I have said to you that no one can come to Me unless it has been granted to him by My Father.”
66 From that
time many of His disciples went back and walked with Him no more. 67 Then Jesus said to the twelve, “Do you also want to go away?” 68 But Simon Peter answered Him, “Lord, to whom shall we go? You have the words of eternal life. 69
Also we have come to believe and know that You are the Christ, the Son of the living God.”
70 Jesus answered them, “Did I not choose you, the twelve, and one of you is a devil?” 71 He spoke of Judas Iscariot,
the son of Simon, for it was he who would betray Him, being one of the twelve. John 6:60-71
JLB