A couple of my own recent "failures" in ministry have jostled my confidence, and they have prompted me to think theologically about the word. How does Scripture see failure? Can a Christian fail in God's eyes? Does it matter to God when we fail in our jobs or our relationships?
The Biblical sense of "fail" covers a spectrum of nuance. In the Old Testament, it generally refers to a food or some staple being used up before it can be replenished. For instance, in the story of Elijah and the Widow of Zarephath in 1 Kings 17, God promises that "the jug of oil will not fail" the famished woman and her household. This definition of "fail" strikes me in my own case, as I felt the quality of my efforts sufficient but the circumstances did not dictate "success" (another term that needs desperate definition in church leadership).
In the New Testament, the word we translate as "fail" is also the same word we translate as "sin". "Sin" is a term that simply means "missing the mark", an archery word. Notice that it does not entail evil intention (as we often want to color sin) necessarily, but rather that we do not reach an expected intention. For God's people, that intention is God's Kingdom. When we participate in evil ways, we miss the mark of that goal. Thankfully, we believe in a merciful God and a (hopefully) forgiving community who lets us keep on trying.
So, yes, I think we can fail in God's eyes. In the first sense, we can give all of the effort within us to one good task and still run out of steam. But the God in Jesus who poured himself out fully (Philippians 2:7) can re-fill us to no end. And in the second sense, we may stray from our mark no matter what our intentions. But we are called to try with all our heart (see Romans 14:5-7; I am also thinking here of the Lutheran exhortation to "sin boldly"), and God will keep handing us a new arrow from the quiver.
The truth is that we will fail in many aspects of our lives. We will even have epic fails. Our confidence may even be shattered in the process. But God will not fail and God will not fail us (in both senses of the word). In fact, I hope we can recognize this to the point that we can laugh about it (seriously, click on the links in the first paragraph).