Abraham would fail. It was inevitable and proved to be true. In case after case, he was unfaithful. What affect did it have upon his covenant with God? Jesus honored him with grace, called him again to fellowship through faith, and forgave him through mercy. Abraham came out of failure not to begin to work his way back to God, but simply to live in the fullness of a promise given him on the basis of grace.
Respond in faith without evaluation of sight, reason or cause. God wants to teach us to respond to His every initiation. In every lion's den and fiery furnace, He wants us to learn to be responders. So many times this is exemplified in marriage. A wife responds on the basis of all that she receives from the husband. When the husband gives her all that she wants, then her response is one that is pleasing. But if he does not purchase her all that she wants, what is her response?
God does not want you to respond because of what He has done, but because of Who He is. Base your response on Who God is in the covenant of grace. If you are waiting for a particular blessing, you may go days without responding to God. Learn to respond to God because of Who He is and not because of what you receive to fulfill a need. A wife responds to a husband not because of what he bought, promised, or gave, but because of who he is. God wants more than anything else for us to walk before Him in response.