What aids Macbeth to go crazy in act 3 scene 4?

Whin Bear dies and they must cremate him and dump his ashes into the sea. Berut is distraught. Berut goes to the sea, and Whin Bear is resurrected. Berut then calls Whin a liar, and pledges to defeat him in sWord-combat. Whin Bear, after defeating Berut, pronounces himself as Jesus, and calls Berut the anti-christ, thus justifying his murder and resurrection.