God who created the universe, the heavens, the earth and all that is in it is the Ruler of all. Only the Creator God has the wisdom, power and authority to rule with righteousness and with justice and mercy.

The story of Daniel, a captive of the King of Babylon, tells of tragedy, courage, faith, adventure, and a truth we all need to know:

The decision is announced by messengers, the holy ones declare the verdict, so that the living may know that the Most High is sovereign over the kingdoms of men and gives them to anyone he wishes and sets over them the lowliest of men.
Daniel 4:17

The King of Babylon, Nebuchadnezzar “was driven away from people and given the mind of an animal; he lived with the wild donkeys and ate grass like cattle; and his body was drenched with the dew of heaven until he acknowledged that the Most High God is sovereign over the kingdoms of men and sets over them anyone he wishes” (Daniel 5:21).

Daniel was given visions of a future beyond our time. In this future, he saw a future king and a future kingdom:

In my vision at night I looked, and there before me was one like a son of man, coming with the clouds of heaven. He approached the Ancient of Days and was led into his presence. He was given authority, glory and sovereign power; all peoples, nations and men of every language worshiped him. His dominion is an everlasting dominion that will not pass away, and his kingdom is one that will never be destroyed.
Daniel 7:13-14

Jesus referred to himself as “Son of Man.”

Again the high priest asked him, “Are you the Christ, the Son of the Blessed One?” “I am,” said Jesus. “And you will see the Son of Man sitting at the right hand of the Mighty One and coming on the clouds of heaven.”
Mark 14:61b-62

Jesus was asked by Pilate if he was a king.

Jesus answered, “You are right in saying I am a king. In fact, for this reason I was born, and for this I came into the world, to testify to the truth. Everyone on the side of truth listens to me.”
John 18:37

He also told Pilate “You would have no power over me if it were not given to you from above” (John 19:11).

In the Revelation of Jesus Christ given to John, Jesus gives us a picture of the works and character of his churches, calling all to repentance and perseverance.

We are also shown the Lamb being worshiped:

You are worthy to take the scroll and to open its seals, because you were slain, and with your blood you purchased men for God from every tribe and language and people and nation. You have made them to be a kingdom and priests to serve our God, and they will reign on the earth.
Revelation 5:9-10

In one sense, the kingdom of God Jesus preached is on earth now ruling those who are now citizens of his kingdom through faith (Ephesians 2:11-22; Philippians 3:20-21); but there is a kingdom coming in which all nations will be subject to the Sovereign Ruler of the universe (Revelation 11:15; 1 Corinthians 15:23-28, 49-57).

Babylon, a symbol for the systems of this world, will fall before God's judgment for its sins (Revelation 18:1-24). God’s people are warned to “Come out of her” so we will not share in her punishment (Revelation 18:4-8).

Jesus prayed for us all when he said, “I have given them your word and the world has hated them, for they are not of the world any more than I am of the world. My prayer is not that you take them out of the world but that you protect them from the evil one. They are not of the world, even as I am not of it” (John 17:14-16).

The call to come out of the sins of this world is by the blood of Jesus, faith that he took our judgment upon himself (Revelation 12:10-12). We don't need to know the “when” of Jesus' second coming; we only need to know Jesus as our Lord and Savior. We need to know that God rules in the kingdoms of men.