I understand the faith that God looks for to be far beyond simply a belief that He is real. The Bible tells us even the demons believe that and tremble. When the Israelites chose fear instead of trusting God, and His promise of the Promised Land as well as His promise to be with them in the occupation of it, God said they despised Him and didn't believe in Him (Numbers 14:11). He also says that their failure was because they didn't have faith (Hebrews 4:2) and this was, in His eyes, disobedience (Hebrews 4:6).
Did the Israelites believe God existed? Absolutely. But they didn't believe in Him (as in His nature and character and goodness and love). When we say we believe in another person we aren't saying we believe they exist, we are saying we have confidence in them. The Israelites didn't commit themselves and their life choices into a relationship of trust with Him. And so often God calls us the same way. He points us in a direction, and says, "I'll be with you." Often we are acutely aware of the obstacles in front of us (as was Moses, Joshua, Gideon, etc.). Then He waits for our choice—sight, fear, etc., or a commitment into a trust relationship with Him and the promise of His presence . . . faith.
How important is this type of faith relationship to God, where we act in our life based on our trust in Him? Romans 14:13–23 is a stunning revelation of it—one that will rock our "religious roots" to their core. Paul is saying how he knows all food has been made clean, but that some brothers in Christ aren't convinced. He warns against grieving them in our choices, or to make them stumble (lead them into eating something they are convinced in their heart it is OK to eat). Please read the following verses and then I'll share what to me is an amazing thought about them . . .
Do not, for the sake of food, destroy the work of God. Everything is indeed clean, but it is wrong for anyone to make another stumble by what he eats. It is good not to eat meat or drink wine or do anything that causes your brother to stumble. The faith that you have, keep between yourself and God. Blessed is the one who has no reason to pass judgment on himself for what he approves. But whoever has doubts is condemned if he eats, because the eating is not from faith. For whatever does not proceed from faith is sin. (Romans 14:20–23)
On the surface—the first read—what God is saying through Paul is simple enough. "You know that food is OK. I've made it OK. But don't cause them to stumble though, if they don't think it is OK." But then we realize what God is really saying, and it challenges everything in us that is still tied to works instead of relationship as a basis of our salvation and acceptance before God.
What is God really saying here? How about, "I would rather have a child theologically incorrect but living in a committed faith/trust/love relationship with Me that directs their life, then have a child be theologically 'perfect' and not be living in that faith relationship with Me." Wow! Our faith is more important to God than our getting every theological point perfect! And the true is same of love. He is going to far more bless something we do in love that may not be just right, than the perfect act or words we do/speak that aren't in love. This is a stunning insight into God's heart, and it makes sense. Trust and a commitment in love and trust to a person—a commitment that drives our life—is far more important than getting it all perfect (all the right words and theology and works) apart from love and trust. And, if we think about it, we'd value the same things in any human relationship we were involved in as well . . .