Luke 4:6 - And the devil said to Him, “All this authority I will give You, and their glory; for this has been delivered to me, and I give it to whomever I wish. New King James Version
Notice that the Devil has authority over the whole world, and he delegates authority to whomever he wishes.
Jesus refers to Satan as the “ruler of this world” (John 12:31; 14:30; 16:11). Christ recognizes Satan as the present ruler of the world. However, Satan does not rule alone. He has a whole army of fallen angels, called demons, at his disposal.
The apostle Paul refers to these evil rulers in his letter to the Ephesians. “For we do not wrestle againstflesh and blood, but against principalities, against powers, against the rulers of the darkness of this age, against spiritual hosts of wickedness in the heavenly places” (Ephesians 6:12).
These demons may number in the multiple millions (compare Revelation 5:11 and Revelation 12:3-4).
The Bible shows us how these evil forces influence the rulers of the nations. An example occurs in I Kings chapter 22.
When Ahab, the evil ruler of Israel, is trying to decide whether to fight against Syria to retake Ramoth Gilead, Jehoshaphat, the king of Judah, persuades him to consult his prophets first. All of his prophets tell him to proceed with the battle because God would give him a great victory. However, Micaiah, a true prophet of God, tells him that God had allowed an evil spirit to put lies into the mouths of Ahab’s prophets. This is because it is God’s purpose that Ahab be killed in the battle. Ahab shuns Micaiah, takes the advice of his own prophets, and is killed while fighting the Syrian armies.
As Christians, God encourages us to be strong and keep our faith standing to overcome all works of evil. There will be many tests and trials and sometimes these sufferings that happen to us are all because God had given Satan the permission to test us. It happened with the servant of God, Job. If it did happen to him, then expect that it will also come to us.
The authority given to Satan aims to test us. If we fail on those tests, then Satan will be so much happy… our lost, his gain. Although some tests or shall we say, temptations came from the devil, God trust us that we will succeed, because He believes in us, He had given us the strength we need to overcome everything in this life. Php 4:13 I can do all things through Christ which strengtheneth me.