"The people walking in darkness have seen a great light;
on those living in the land of the shadow of death, a light has dawned."
Do not doubt in the dark what you have seen in the light. When a great storm comes upon you and knocks out the power, you blindly stumble throughout the house. Suddenly a flash of lightning shakes the house and illuminates the room. For the briefest of moments, you know where you are and how to get to where you are going. When the room fades again to black, the reality of the room does not disappear but rather is hidden.
Such is faith to us, like lightning in the deep dark of night. Amidst the sea of doubt and the fog of suffering, our God is a lighthouse, a salvation for those lost at sea. And you only need to see it once through the cracks of obscurity to forever know it is there, seen or unseen. We walk in the light whether the light shines or not because it's there whether we see it or not.
But what we cannot do is convince another of what we have seen. All they see is dark and fog without the light. Only by trust would a man believe solely upon our word, but it would not be real in his mind until he sees what we saw in the light. All we can do is simply tell him where to look when the lightning strikes.