Paul used Abraham as the example of true faith in Romans 4. What does faith really look like? How does faith act in the face of obstacles that threaten to undo it? Look at Romans 4:16-21 (NASB):
"For this reason it is by faith, in order that it may be in accordance with grace...to those who are of the faith of Abraham, who is the father of us all...in hope against hope he believed...without becoming weak in faith he contemplated his own body, now as good as dead since he was about a hundred years old, and the deadness of Sarah's womb; yet with respect to the promise of God, he did not waver in unbelief but grew strong in faith, giving glory to God, and being fully assured that what God had promised, He was able to perform."
OK, here is the gig - Hebrews 11:6 says one cannot please God without faith. Faith is just that important. But faith is not only a subjective trust in something one wishes to be true. Romans 10:17 says that faith comes from hearing the Word of God. God speaks His Word (the Scriptures) to His sheep, and Jesus' sheep hear the voice of their beloved Shepherd in the words of the Scripture. And as a result, the sheep believe Jesus and His Word. The sheep have faith in what Jesus says in the Scripture.
Faith says several important things. (1) Faith says, "I want to get God's Word right; I want to rightly interpret the Word of God." (2) Faith says, "I will rest my convictions, my hopes, and my expectations on what God has said in His Word; He cannot fail in any promise He makes." (3) Faith says, "I will trust God to bridge the gap from the promise of the Word to my personal human experience; I will not put demands on God, but rather, I will trust God to be true to Himself in fulfilling His Word." (4) Faith says, "I will not quit believing God no matter what I see or don't see, what I feel or don't feel; sight and feelings do not verify God." (5) Faith says, "I will smile always knowing that God will certainly come through to do what is best, wisest, and good for me."
But there is one more thing; something bothers me about the reference to Abraham and faith in Romans 4. If one reads the story of Abraham and Sarah and the promise of God, one realizes that there is a disconnect here. Abraham and Sarah tried to work out God's promise with their own rationale and in their own strength. They tried to accomplish God's will by conniving and scheming and working their own plans. And it failed MISERABLY! But when I read Romans 4 about Abraham and his faith, I see absolutely no reference to Abraham's failure of faith. Rather, Abraham is presented as a model of faith. Did God forget the failure of Abraham? No, but God chose to overlook the failure of Abraham. The greatest of people are rotten failures in the eyes of God. This is a given; no question or debate. Someone has rightly said, "The best of men are men at best." But God's grace moves beyond the failures of His people, and God shows His glory in their successes, because those successes demonstrate God's grace in the lives of His people. God is not keeping a book of your mistakes in order to "pound" you one day with judgment. All of your sins and failures are nailed to Christ's cross, and the debt has been paid in full. Paul may have called himself the chief of sinners, but God never called Paul that. To God, Paul was one of His chosen ones whom He loved with all His heart.
So, Christian friend, trust God, lean on God, rest in His promise and faithfulness. Stop beating yourself up for your failures, and live by FAITH!