My dad told me one time, "when Moses struck the rock a second time, he was wrong... but water still came out" (see Numbers 20:7–13). I've thought about that comment many, many times. It's entirely possible – even likely – that God will bless us regardless of our obedience or our disobedience. God's blessing isn't evidence that we are obedient, it's evidence that God is good. In the story of the water from the rock, everyone was wrong except God; but He still gave them what they needed.
So let's don't allow ourselves to fall into the trap of thinking that God's blessing is proof of our own goodness. It isn't. A friend told me many years ago (quoting someone else), "God blesses us because He is good, not because we are."
But the fact remains that I'm not terribly interested in a Christianity that doesn't actually work. And this brings me to a sort of a conundrum: on the one hand, faith is believing that God has said. "The just shall live by faith," is really the central message of Romans (Romans 1:17), Galatians (Galatians 3:11), and Hebrews (Hebrews 10:38). There's not much more central than that!
But on the other hand, the epistles teach a transforming sort of faith. 2 Corinthians 4:6 tells us that the same God who commanded light to shine out of darkness has shone in our hearts. God's having called light to shine out of the darkness of our hearts (which is really the point Paul is making) suggests a visible effect.
Note I'm not talking about counterfeit spirituality. I am convinced nothing has done more to hurt the testimony of believers than trying to produce spiritual fruit from carnal energy. And I suppose that's really the point I'm trying to make. Moses and Aaron acted carnally at Meribah, but water still came out. See, it's possible to act with fleshly energy, and still see tremendous blessing. Isn't that what Philippians 1:15–20 teaches? It's possible to preach Christ out of envy, out of a desire for strife. And it's possible people will be brought to repentance out of it, not because God approves of the preaching, but because God blesses out of His own goodness.
I know for a fact that we can be fleshly in our preaching, our prayer, our Bible study, and even our declaring the Gospel. We know for a fact that God can and does bless us, and through us, even when we're acting badly, even when we're flat-out wrong. And seeing "results" isn't proof that we're right, it just means that God is acting like He always does – out of grace.