Jesus' well-known Olivet Prophecy contains probably the most familiar description of Christ's return:
Then the sign of the Son of Man will appear in heaven, and then all the tribes of the earth will mourn, and they will see the Son of Man coming on the clouds of heaven with power and great glory. (Matthew 24:30)
Other passages describing this event echo a common element. While some of these verses also speak of “power” and “glory,” the common element in all these descriptions is the mention of clouds.
This detail at first may not seem relevant, but it shows up repeatedly. Why did God consistently inspire the Bible's writers to include that little detail? We know that He does not inspire empty or superfluous words; everything about His revelation is deliberate and meaningful. What meaning do the clouds hold in the Bible? Why are they significant to the return of our Savior to the earth?
Consider what a cloud is and does. By way of definition, a cloud is “a visible mass of droplets of water or frozen crystals, suspended in the atmosphere.” Sometimes clouds bring rain, which can be either a blessing or a curse depending on the circumstances, but other times they pass by without sharing a drop. Nevertheless, there is one thing a cloud will always do, if it has any size at all: It will impede light, such as the light of the sun or the moon. Since it is clothing Jesus Christ, this cloud filters some of His breathtaking glorious radiance.
This is not the only way the Bible uses clouds. It also uses them to represent multitudes of people (Isaiah 60:8; Hebrews 12:1), the sins of men (Isaiah 44:22), or the impermanence of the wealth of the wicked (Hosea 6:4; 13:3). They can represent the empty words of false teachers (Jude 12; II Peter 2:17), the unfulfilled promises of faithless men (Proverbs 25:14), and a number of other things. But when the clouds surround God Himself, they are a covering that mercifully impedes His full brilliance. They represent the unsearchableness of God, His mysterious depths, and how futile it is for carnal men to try to understand His ways (II Samuel 22:12; Psalm 97:2; Ezekiel 1:4).
This covering is critical because the undimmed brightness of a God-being is lethal to mankind. Moses had to be hidden from the full glory of God in the cleft of a rock, or he would have died (Exodus 33:19-23). After that, the Israelites could not stand to look at Moses' face, and he had to use a veil—a cloud made of cloth, if you will—because even when the glory of God was reflected and vastly dimmed, it was too much to take (Exodus 34:29-35).
As already mentioned, Jesus Christ will be returning in glory, and that awesome glory has a terrible, lethal effect on sinful flesh. In particular, II Thessalonians 2:8 foretells that “the lawless one” will be “consume[d] with the breath of His mouth and destroy[ed] with the brightness of His coming.” Apparently, Christ will not always remain behind a cloud but will allow His full glory to show for the purpose of destroying unholy men.
We can thus see why being surrounded by clouds is an act of mercy on God's part: Mere men cannot abide the sight of One so pure and holy.