Do you know how to digest your food? Do you know how to fill your lungs with air? Do you know how to establish, regulate and direct the metabolism of your body -- the assimilation of foodstuff so that it builds muscles, bones and flesh? No, you don't know how consciously, but there is a wisdom within you that does know.
You don't decide to build a church because you have money in the bank. You build because God says this is what I should do. Faith is the supplier of things hoped for and the evidence of things not seen.
It could be that our faithlessness is a cowering cowardice born of our very smallness, a massive failure of imagination. If we were to judge nature by common sense or likelihood, we wouldn't believe the world existed.
Justifying faith implies, not only a divine evidence or conviction that God was in Christ, reconciling the world unto Himself, but a sure trust and confidence that Christ died for my sins, that He loved me and gave Himself for me.