For the Lord your God is God of gods and Lord of lords, the great God, mighty and awesome, who shows no partiality nor takes a bribe.
Deuteronomy 10:17

 Recommended Reading: Isaiah 44:6

The title “king of kings” goes back to the thirteenth-century B.C. Assyrian Empire. When city-states, ruled by kings, were conquered, the conquering king would become known as the “king of [all the other] kings.” It became a superlative phrase referring to preeminence—the most powerful king (Daniel 2:37).

The phrase became common throughout Mesopotamian and Middle Eastern cultures to describe the best of the best—as in the biblical book titled “Song of Songs.” It is even used to describe the God of Israel in various forms: “God of gods” and “Lord of lords” (Deuteronomy 10:17; Psalm 136:2-3), the “Lord of kings” (Daniel 2:47), and Jesus Christ (1 Timothy 6:15; Revelation 17:14; 19:16). When referring to our God, what does this ancient phrase mean for us today? It means God is ruler over all; He is in charge; He is King of the present and the future.

In a day when it is easy to wonder if anyone is in control, remember that there is only one “God of gods.” His will will be done on earth as well as in heaven.

How divinely supreme is our Lord above all others! 
D. Martyn Lloyd-Jones

https://www.davidjeremiah.org