Scripture often employs the imagery of blindness to describe the spiritual condition of persons who are either unable or unwilling to perceive divine revelation.
The things of God are perceived not by observation and inquiry, but by revelation and illumination.
Matt 11:25-27 At that time Jesus said, I praise you, Father, Lord of heaven and earth, because you have hidden these things from the wise and learned, and revealed them to little children. Yes, Father, for this is what you were pleased to do. All things have been committed to me by my Father. No one knows the Son except the Father, and no one knows the Father except the Son and those to whom the Son chooses to reveal him.