There is a mystery involved in why God allows Satan to continue when He could destroy him at any time [God will not violate His own rules].

But Jesus Christ will finally destroy Satan 'by the brightness of His coming'.

The contrast between them is summed up:
Feature     Christ      Antichrist
Origin      Heaven      Bottomless Pit
Nature      Good        Idol
            Shepherd    Shepherd
Destiny     To be       To
            exaled on   cast down to
            High        Hell
Goal        To do His   To do his
            Father's    own will
            will
Purpose     Save the    Destroy God's
            Lost        God's people
Authority   His         His own
            Father's    name
            Name
Attitude    Humbled     Exalts
            Himself     himself
Fruit       True Vine   Vine of
                        the earth
Response    Despised    Admired