a cloud: in the New Testament, almost always the visible sign that God is present and on the move
On its own this word means simply a "cloud" in the sky, and ordinary Greek used it that way for plain weather. The New Testament uses it that plainly only once. Everywhere else it has been filled with meaning carried over from the Old Testament, where a cloud descends on Mount Sinai, leads Israel through the wilderness, fills the tabernacle, and settles on the temple. In all those places the cloud is how a God too great to be seen makes himself present in one spot: it both shows that he is there and shields people from looking straight at his glory.
The senses below are not different dictionary meanings of the word. They are the different jobs the one cloud does.
- It marks God's presence (the bright cloud at the mountain where Jesus is transformed, the cloud Israel walked under at the Exodus).
- It carries figures between earth and heaven (the cloud that lifts Jesus out of sight at the ascension, the cloud the two witnesses rise in).
- And, drawing on Daniel's vision of a humanlike figure who comes with the clouds of heaven, it becomes the sign of Jesus' final, public coming in triumph.
The most striking thing the New Testament does with the word is to take the cloud that once belonged to God alone, the chariot he rides and the glory that veils him, and attach it to Jesus. Jesus comes with the clouds, is taken up in a cloud, and meets his people in the clouds. That transfer is one of the quietest but strongest signs that the first Christians placed Jesus on God's side of the line.
Two uses run against this grain and are worth keeping separate. One is the single plain weather report, where a rising cloud just means rain is coming. The other is a sharp insult: false teachers are called waterless clouds, all the look of rain with none of the relief, blown past without delivering anything.