A.T. Robertson Commentary John 12:31

"Now is the judgment of this world: now shall the prince of this world be cast out." — John 12:31 (ASV)

The judgement (κρισις). No article, "A judgement." The next few days will test this world.

The prince of this world (ο αρχων του κοσμου τουτου). This phrase here, descriptive of Satan as in possession of the evil world, occurs again in 14:30; 16:11. In the temptations Satan claims power over the world and offers to share it with Jesus (Matthew 4:8–10; Luke 4:5–8). Jesus did not deny Satan's power then, but here proclaims final victory over him.

Shall be cast out (εκβληθησετα εξω). Future passive of εκβαλλω. Note εξω, clean out. The Book of Revelation also proclaims final victory over Satan.