John 6:62 – “where he was before”
This verse (John 6:62) is referring to the resurrection of Christ, not the ascension of Christ up to Heaven.
The translators have chosen to translate the Greek word anabaino (G305) as “ascend up” instead of “arise.” As a result, many people believed it referred to Christ’s ascension from earth as recorded in Acts 1:9, however, Acts 1:9 does not use this word.
Jesus was speaking about being the bread from heaven and giving life via his resurrection. Jesus was teaching the Jews about his yet FUTURE death and resurrection. This would show that he had conquered death and was ALIVE forever more and that he was indeed the SON of Almighty God.
Remember many Jewish leaders did not believe in the resurrection at that time (Mat 22:23).
In addition, Jesus said, “I will raise him up [any believer] at the last day” (John 6:39, 40, 44).
Of course, Jesus had also been speaking of the resurrection (the last day) in addressing their concern about eating His Flesh and drinking His Blood to receive this eternal life (John 6:27-28, 54). When they took offense (John 6:60-61) Jesus exposed their unbelief, by asking them if they would also be offended if they saw him “arise” (from the dead, resurrected) and be where he was before, i.e., alive and on the earth. (1Cor 15:3-8, John 6:62, 66)