'Your Word is a lamp to my feet, and a light for my path.' (Psalm 119:105)
God considers human reason, morality, and even sunlight for that matter, to be dark and hazy compared to his Word. God's Word is flame that shines in the darkness. Through teaching, preaching, and the sacraments, its glow spreads. If we use this light, then God will no longer remain hidden from us.
When we're faced with disasters, when we're overwhelmed by darkness, when things seem so dark that we doubt that we are part of the church or pleasing to God, then we should learn to reach for the Bible. We shouldn't let people who fall away from the faith distract us. Instead, we should recognize that we live in a dark world. The only reason we can see at all is that the light of God's Word shines brightly (2 Peter 1:19)
Jesus said, 'whoever believes and is baptized will be saved (Mark 16:16). The light of these words is shining in our hearts. Even if the sun were shining brightly, it couldn't reveal this truth. Human reason by itself can't grasp it. Wherever the Bible sheds its light, no real danger exists. Without the Bible, we wouldn't know or understand anything.
Martin Luther-reprinted "Through Faith Alone" Concordia Publishing, St. Louis