The devil is not a supernatural being, but a personification of sin in its various forms. This figure of speech gives personality to our inward impulses opposed to God. This is demonstrated quite simply in Matthew's gospel chapter 4 where we have an account of Jesus' temptations in the wilderness of Judea. Here, both “the Devil” and “Satan” are in the text. The temptation narrative is a vivid word picture combining literal fact with figurative imagery.
Jesus was led into the wilderness to be tempted by “the devil”. This is where he had a great mental struggle which he overcame. When Jesus was hungry he was tempted to use his power to turn stones into bread. Also, he was taken to a very high mountain where he was shown all the kingdoms of the world and the glory of them, to be told “these things will I give you if you fall down and worship me”. Jesus could not literally see all the kingdoms of the world. These belong to God, not the conventional devil.
All of us are tempted, tested, tried, and provoked so often. This occasion demonstrates the struggle in which the sinless Son of God was engaged, and from which he emerged victorious. He did not sin. In his own words: “I have overcome the world”.
The New Testament writers are quite clear on what it is that causes death: “the wages of sin is death”. Sharing our nature, he destroyed the power of death, that is the devil.
Jesus, by his death could not have destroyed a supernatural devil, but through it he conquered sin, which is personified as “the devil”, and vanquished death itself for all those who believe he can save us.