Did Satan have the power to give Jesus all the kingdoms of the world?
Yes. Satan could offer the kingdoms because, since Adam fell, he is the god of this world. The temptation was real: Satan showed Jesus all the kingdoms and promised them if He would fall down and worship him, but Jesus refused.
Les explains that the devil took Jesus up into an exceeding high mountain and showed Him all the kingdoms of the world. From Jerusalem, geographically central to the then-known world, and with the Roman Empire reaching west to Great Britain, east to India, and involving North Africa and Egypt, they could envision the great empires of history and even the future. Satan then said that if Jesus would fall down and worship him, He could have all of it. Les asks whether it was in Satan’s power to give those kingdoms and answers, “Yes, absolutely.” Many people do not realize this, but since Adam fell, Satan is the god of this world.