60 Many therefore of his disciples, when they had heard this, said, This is an hard saying; who can hear it?

[Many therefore of his disciples] So it appears that he had many more than the twelve, who constantly accompanied him.

[This is a hard saying; who can hear it?] Who can digest such doctrine as this? The wicked word of a lying world is in general better received than the holy word of the God of truth.

61 When Jesus knew in himself that his disciples murmured at it, he said unto them, Doth this offend you?

[Jesus knew in himself] By giving them this proof that he knew their hearts he also proved that he was God; that he could not be deceived, and that it was impossible for him to deceive any; consequently, the doctrine he taught them must be the truth of God.

62 What and if ye shall see the Son of man ascend up where he was before?

[If ye shall see the Son of man ascend] You need not be confused by what I say concerning eating my flesh and drinking my blood, for you shall soon have the fullest proof that this is figuratively spoken, for I shall ascend with the same body with which I shall arise from the dead; therefore, my flesh and blood, far from being eaten by men, shall not even be found among you.

63 It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they are life.

[It is the spirit that quickeneth] It is the spiritual sense of my words that is to be attended to, and through which life is to be attained (2 Corinthians 3:6).

[The flesh profiteth nothing] Even if ye could eat my flesh and drink my blood, this would not avail for your salvation.

[The words that I speak...are spirit...and life] Look ahead to verses 68 and 69. Peter understood.

64 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 that believe not] This is addressed to Judas and those disciples who left him. Verse 66.

[And who should betray him] Because he knew all things he knew from the first, from Judas call to discipleship, even from eternity, who it was who would deliver him up into the hands of the Jews. Foreknowledge did not irrestibly compel Judas to do so, but God knew who, by his own free will, would choose to betray Jesus.

65 And he said, Therefore said I unto you, that no man can come unto me, except it were given unto him of my Father.

[Therefore said I unto you] Referring to verse 44 of this same chapter. See the comments regarding John 6:44.

66 From that time many of his disciples went back, and walked no more with him.

[Many of his disciples went back] They no longer associated with him or professed him as the Messiah. None of these were the twelve. Christ had many others who generally attended his ministry and acknowledged him as the Messiah.

67 Then said Jesus unto the twelve, Will ye also go away?

[Will ye also go away?] We know that Jesus already knew the state of their hearts but he also knew it would be good for them to give voice to their belief.

68 Then Simon Peter answered him, Lord, to whom shall we go? thou hast the words of eternal life.

[Then Simon Peter answered] With his usual zeal and readiness to speak in behalf of the whole, To whom shall we go? Where shall we find a more gracious master - a more powerful Redeemer - a more suitable Savior. Thou alone hast the words of eternal life. None can teach the doctrine of salvation but yourself. None can confer the gift of eternal life but you alone.

69 And we believe and are sure that thou art that Christ, the Son of the living God.

[We believe] On the authority of your word, and are sure by the evidence of your miracles, that you are the Christ, the promised Messiah.

70 Jesus answered them, Have not I chosen you twelve, and one of you is a devil?