Let me be as clear as possible: God alone is supreme, and He alone is above every other spiritual power in the universe. When Jesus was asked which was the most important commandment in the Old Testament, He began with these words: "Hear, O Israel, the Lord our God, the Lord is one" (Mark 12:29).
Yes, God is the sovereign spiritual power over all creation—but He isn't the only spiritual power. Before time began, He created the angels—a separate category of spiritual beings. They were never equal with Him, nor will they ever be; their power is limited, and they are strictly under His control. They were created to do His will—including watching over His children. The Bible says, "For he will command his angels concerning you to guard you in all your ways" (Psalm 91:11).
The Bible tells us, however, that some of the angels rebelled against God. They followed one of the highest ranking angels, who came to be called Satan (which means "adversary"). Since that time, Satan has done everything he can to oppose God and put himself in God's place.
Yes, Satan is real; you see his work every day. But listen: Satan is a defeated foe! By His death and resurrection Jesus overcame the devil. Don't be deceived, but make sure you are on the winning side by committing your life to Jesus Christ today.