The Bible states that God “alone has immortality” (1 Timothy 6:13–16). This means that no other creature in the universe is immortal on its own. As a created angel, this fact equally applies to Satan, formerly known as Lucifer, who once held the highest position in God’s throne room.
Also, the Bible directly states that “the soul who sins shall die” (Ezekiel 18:20). Nephesh, the Hebrew word from which we get the word “soul,” includes the meaning of “creature” and “living being.” So this verse applies not only to human beings but also to angels. Not only has Satan sinned, but he is the originator of sin. Jesus said to those religious leaders who chose disbelief, “You are of your father the devil. … He was a murderer from the beginning, and does not stand in the truth, because there is no truth in him. When he speaks a lie, he speaks from his own resources, for he is a liar and the father of it” (John 8:44). Since Satan is a living being, and since he is the originator of sin, he will certainly experience the consequence of sin—death. “The wages of sin is death” (Romans 6:23).
Jesus spoke of “the everlasting fire prepared for the devil and his angels” (Matthew 25:41). Does this mean that Satan will burn forever and ever in eternal misery? There is a Bible passage that explains both parts of the question we are analyzing. God was speaking to Satan:
“By the abundance of your trading you became filled with violence within, and you sinned; therefore I cast you as a profane thing out of the mountain of God; and I destroyed you, O covering cherub, from the midst of the fiery stones. Your heart was lifted up because of your beauty; you corrupted your wisdom for the sake of your splendor; I cast you to the ground, I laid you before kings, that they might gaze at you. You defiled your sanctuaries by the multitude of your iniquities, by the iniquity of your trading; therefore I brought fire from your midst; it devoured you, and I turned you to ashes upon the earth in the sight of all who saw you” (Ezekiel 28:16–18).
Is Satan immortal? God said that Satan would be devoured. Will Satan burn forever in hellfire? God said that in the sight of everyone, Satan will be turned to ashes.