We tend to say that because a person has natural ability, he will make a good Christian. It is not a matter of our equipment, but a matter of our poverty; not of what we bring with us, but of what God puts into us; not a matter of natural virtues, of strength of character, of knowledge, or of experience— all of that is of no avail in this concern. The only thing of value is being taken into the compelling purpose of God and being made His friends (see 1 Corinthians 1:26-31). God’s friendship is with people who know their poverty. He can accomplish nothing with the person who thinks that he is of use to God. As Christians we are not here for our own purpose at all— we are here for the purpose of God, and the two are not the same. We do not know what God’s compelling purpose is, but whatever happens, we must maintain our relationship with Him. We must never allow anything to damage our relationship with God, but if something does damage it, we must take the time to make it right again. The most important aspect of Christianity is not the work we do, but the relationship we maintain and the surrounding influence and qualities produced by that relationship. That is all God asks us to give our attention to, and it is the one thing that is continually under attack." Aug. 4, My Utmost for His Highest 
I don't know why God chooses to trust us. But He does. And it's for His purpose, and His kingdom. It is for His purposes that we are to live, trusting Him that He is good towards us. I am of little worth to Him, especially right now as there is nothing for me to do. But I love Him, and can't imagine making it through all that He has set before me without Him. His strength sustains me. His love holds me. I do not know His purpose, and there is a great chance that I will not enjoy or like the way this season turns out, but His heart hurts with mine, and I can trust Him. Because of His cross my debt is paid, and there is more than this earth.