Throughout Scripture the cloud has repeatedly appeared as evidence of God’s presence. He himself, after all, is too glorious for the human eye to behold. So the Lord led Israel out of Egypt in a “pillar of cloud” (Exodus 13:21) and came down on Mount Sinai in “a thick cloud” (Exodus 19:16). The psalmist pictures God as riding clouds as if they were his chariot (Psalm 104:3; see also Psalm 18:10). On the Mount of Transfiguration God came to Jesus and the three disciples with him in a cloud (Luke 9:34f). So when a cloud appeared at Jesus’ ascension to carry Jesus out of the disciples’ sight (Acts 1:9), there could be no doubt that God himself was carrying Jesus aloft into heaven and so publicly giving his stamp of approval to Jesus’ work. The same is true at the ascension of the two witnesses into heaven.
12 Then they heard a loud voice from heaven saying to them, “Come up here!” And they went up to heaven in a cloud, and their enemies watched them.