To be unable to see the path to heaven, unable to grasp God's truth; by nature every human being has a veil over his eyes which prevents him from taking God at his word and trusting his promises. The Holy Spirit gives spiritual sight when he brings people to faith through the means of grace (2 Corinthians 4:4, 2 Corinthians 3:14-16, Colossians 1:13-14).