The very word God implies and requires sovereignty. This is why the word gods implies a contradiction: because the so-called gods imply by that title sovereignty, which they do not possess, they can only be seen as partially gods, i.e., one god controlled sea voyages; another, sexual matters; still another, warfare; and so on and on. Polytheism has many partially ruling spirits, but no God.
The word God implies ultimacy and the power to create, as Scripture often declares: Of old thou laid the foundation of the earth: and the heavens are the work of thy hands (Ps. 102:25). Jesus Christ, as God incarnate, tells His people, Come ye blessed of my Father, inherit the kingdom prepared for you from the foundation of the world (Mt. 25:34). Because God is the only Maker of heaven and earth (Gen. 1:1), it follows that His Word alone can govern all things in every sphere. Because He alone has made us and can save us, His Word alone can govern us. Because He alone is God, His law alone can truly rule us.
Today, however, a church deep into heresy sees Christ as our Savior from sin, but not as our Lord and lawgiver. This is to deny Christ's deity and sovereignty. We have forgotten that, in the early church, to be a Christian was, among other things, to be under a higher Lord and a higher law.
Today, however, I hear preachers deny the sovereignty of God and who see this as an alien doctrine. In effect, they affirm that other powers rule creation, and Jesus has jurisdiction over a corner of it. This is heresy, not Christianity. When terms such as lord, lordship, sovereignty, dominion, and the like are absent from preaching, so too is the Christ of the Bible, however much named.
The sovereignty of God means that the holy Trinity and the infallible Word govern us in every sphere of life. Salvation is not God's only sphere of operation.
When Christians think in terms of God's sovereignty and rule by His law-word, they acknowledge the lordship of Jesus Christ.
In some circles, the word sovereignty is taboo, which in effect means that Christ is also. He is only present where He is truly known as Himself, not as a sentimentalized creature of the church's imagination.
In Matthew 25:31ff., we are told of Christ's coming in His glory to judge all nations. We are then told of those who have professed to know Him reacting with horror at being called the cursed ones because of only a verbal profession of allegiance instead of strong obedience to His total Word. The King's word applies in every sphere of life and thought. He will hold us to it. God is our sovereign because He alone is God.