6:60 Not only "the Jews"(v. 52) but many of Jesus' followers found His teaching about the Bread of Life offensive (Gr. skleros, difficult or hard). The term "disciple"is not synonymous with "believer,"as should be patently clear in the Gospels. In verse 64 Jesus said that some of these "disciples"did not believe. Some of Jesus' disciples were believers, but many of them were following Him to learn from Him and to decide if He was the Messiah or not. This teaching persuaded many in this seeker category to abandon their Rabbi. Some of them undoubtedly wanted the physical benefits of Jesus' messianism but had little interest in spiritual matters (cf. vv. 14-15, 26, 30-31). Others could not see beyond Jesus' humanity to His true identity (vv. 41-46). Others probably could not accept Jesus' claim to be greater than Moses (vv. 32-33, 58). Still others may have found Jesus' language offensive, particularly His references to eating flesh and drinking blood (vv. 53-54).
6:61-62 Evidently Jesus spoke these words to a large group of His followers that included the Twelve. He suggested that He would yet reveal things to them that would be harder for them to accept than what they had heard so far. He had told them that He had come down from heaven (v. 38), and this had scandalized (Gr. skandalizei) them. What would they think if they saw Him ascend into heaven?
Jesus may have been referring to His bodily ascension, but perhaps He was speaking of His crucifixion (cf. 3:14). This explanation is in harmony with Jesus' metaphorical language that He had been using throughout the previous discourse. Jesus' crucifixion was in a sense the first step in His ascending back to the Father since it permitted Him to do so. Certainly Jesus' crucifixion was the most humanly offensive aspect of His entire ministry (cf. 1 Cor. 1:23 where the same Greek word occurs).
6:63 Some of Jesus' disciples turned from Him because they preferred the material realm to the spiritual realm for which Jesus had an obvious preference. He warned them that the Spirit gives real life (cf. Gen. 1:2; Ezek. 37:14; John 3:6) whereas the flesh provides nothing of comparable importance. The words that Jesus had spoken to them dealt with spiritual realities and resulted in spiritual life. Furthermore they were words that came from God's Spirit. Therefore they were extremely important.
6:64 In spite of the importance of spiritual life, Jesus said He recognized that some of His disciples did not believe on Him. This was a tragic irony. They had followed Jesus and had listened to Him, but they did not believe Him.
John added that Jesus knew who did not believe on Him, even who of His disciples would betray Him (vv. 70-71), to show that human unbelief did not take Jesus by surprise.
"Jesus had given ample opportunity for faith to all those who followed him; yet from the beginning his spiritual discernment made him aware of those whose faith was genuine and those whose attachment was only superficial."263
"The beginning"many be a reference to the beginning of Jesus' ministry, but it is probably another reference to Jesus' preincarnate existence (cf. 1:1).
6:65 Again Jesus expressed His belief that the human decision to believe or not believe rested ultimately in God's elective purpose (vv. 37, 44). Thus He did not view the unbelief of His disciples as an indication that He had failed. Notwithstanding He did not present the importance of belief on Himself as something His hearers could take or leave either. It meant the difference between life and death to them, and He urged them to believe.
