We always bring our own experience to the bible, and particularly the Psalms. Here is what the blind theologian John Hull wrote about psalm 139
O Lord, thou hast searched me and known me!
Thou knowest when I sit down and when I rise up; (Ps139 vs1-2)
This is a meditation about knowledge. God knows the posture of my body without having to touch me. 'Thou knowest when I sit down and when I rise up'. God possesses that strange power of knowing at a distance... In some ways, God's knowledge of the world is rather like the knowledge which the sighted have of the blind, but it also goes further...
He goes on to explain that whilst sighted people can read each other's gestures and eye movements, his face and eyes are often misleading to people. His eyes don't communicate anything particularly. Someone might think he was asleep when really he is listening intently to them. For him, everyone is dependent on his spoken words if they are to understand what he is thinking. But not God:
Even before a word is on my tongue,
behold, O Lord, you know it altogether. (Ps 139 vs.4)
"I feel certain that the author of this psalm was blind. Nobody else could have described so powerfully the religious experience of the blind person, or could have interpreted so perfectly the presence of a blind person before God"
His personal insight really helps with these verses too:
If I say, “Surely the darkness shall cover me,
and the light about me be night,”
even the darkness is not dark to you;
the night is bright as the day,
for darkness is as light with you. (Ps 139:11-12)
"Because I am never in the light, it is equally true that I am never in the darkness. I have no fear of darkness because I know nothing else. Nobody can turn the lights out on me. So it is with God. He is indifferent alike to both light and darkness. He does not need the light to know and the darkness does not prevent him from knowing... God does not overwhelm the darkness by his light; he represents that pure knowledge to which both light and darkness in their different ways point"
I find it amazing how the Word of God works for different people. This is not the case of post-modern self-truth where everyone finds something different and everyone's perspective is valid. This is the case where, because Hull is blind, he is able to comprehend aspects of scripture in a different way, and the whole Church benefits from his particular perspective. He sees things that we can't.