The devil lost his exalted position through rebellion (Ezekiel 28:14-17). His judgement is announced in Genesis 3:15.
The cross is the turning point. It is not Jesus who is destroyed, but the devil who loses his rights as ruler of the earth. John 12:31 says: “Now will the ruler of this world be cast out”.
The devil tries to come between God and man. Ephesians 2:2 says: “The prince of the power of the air, the spirit that is now at work in the sons of disobedience.”
One day he will be thrown to the earth (Revelation 12:13). He will then be bound for 1000 years according to Revelation 20:2, and finally banished for all eternity according to Revelation 20:10.
A haughty spirit goes before a fall (Proverbs 16:18). Pride and arrogance lead to failure.