1:10 he went up. Jesus “went up” (as Elijah had long ago—II Kings 2:11) in His physical body, ascending into heaven, where He then “sat on the right hand of God” (Mark 16:19). Thus heaven must be a real place in this physical universe created by God, not some ethereal dimension of time and space entered through a black hole or something of the sort.
1:10 two men. These “two men” witnessing the ascension may well have been the same “two men” at the empty tomb, and even the “two witnesses” who will prophesy in the last days (Revelation 11:3). See discussion on Luke 24:4.