John 12:31 (New International Version)

³¹Now is the time for judgment on this world; now the prince of this world will be driven out.

Jesus is speaking to the disciples about how close is the time that he will be die on the cross. But in doing this, the prince of darkness, will be defeated and Jesus will be victorious over sin. 2 Corinthians tells how the devil has cast his veil of darkness over the earth to hide the good news of the gospel and the free gift of salvation through Jesus Christ.

2 Corinthians 4:3-4 (New International Version)

³And even if our gospel is veiled, it is veiled to those who are perishing. ⁴The god of this age has blinded the minds of unbelievers, so that they cannot see the light of the gospel of the glory of Christ, who is the image of God.

The devil is working nonstop to do his best to hide the gospel and by this leave the unbeliever with a sense of hopelessness leaving them to try to save themselves but salvation comes only through Jesus and not by the works of man.

John 14:6 (New International Version)

⁶Jesus answered, "I am the way and the truth and the life. No one comes to the Father except through me.

Yet another reason why the Great Commission is of such great importance for the believer. To bring the good news to every living soul, pull back the veil of darkness, and show the wonderful goodness and grace of God.

Matthew 9:37 (New International Version)

³⁷Then he said to his disciples, "The harvest is plentiful but the workers are few."