Unwaivering Faith

From Romans 4:20 we read that Abraham never waivered in believing God's promise.  In fact, his faith grew stronger, and in this he brought glory to God.  When I read this, I have a simple question; namely, did Paul read the book of Genesis?  Abraham waivered many times! Maybe God's understanding of faith is different than ours?  When we think of having unwaivering faith, we make no room to doubt, for mistakes, for anxiety.  Perhaps unwaivering faith is a paradox.  Maybe it means we keep coming back to the God who doesn't waiver.