What if you see the Son of man ascend to where he was before? (NIV)
1. This verse is referring to the resurrection of Christ. This fact is clear from studying the context. Because the translators have chosen to translate anabaino as “ascend,” people believe it refers to Christ’s ascension from earth as recorded in Acts 1:9, but Acts 1:9 does not use this word. Anabaino simply means “to go up.” It is used of “going up” to a higher elevation as in climbing a mountain (Matt. 5:1; 14:23, et al.), of Jesus “coming up” from under the water at his baptism (Matt. 3:16; Mark 1:10), of plants that “grow up” out of the ground (Matt. 13:7; Mark 4:7, 8 and 32), or of even just “going up,” i.e., “climbing,” a tree (Luke 19:4). Christ was simply asking if they would be offended if they saw him “come up” out of the ground, i.e., be resurrected, and be where he was before, i.e., alive and on the earth.
2. The context confirms that Jesus was speaking about being the bread from heaven and giving life via his resurrection. Verses such as 39, 40 and 44 confirm this: Jesus repeatedly said, “I will raise him [each believer] up at the last day.” Christ was amazed that even some of his disciples were offended at his teaching. He had been speaking of the resurrection, and they were offended, so he asked them if they would be offended if they saw him resurrected, which has been unfortunately translated as “ascend” in verse 62.
Norton, pp. 248-252
Snedeker, p. 215