From The Saving Life of Christ:
The only ultimate source of divine activity in all spiritual life is God Himself – “Christ in you the hope of glory” (Col 1:27). The Church is so slow to learn. It admires and seeks to emulate the example of the mighty but so seldom takes the trouble “to turn aside and see” the reason why. You read the lives of men like Hudson Taylor, George Mueller, Dwight L. Moody, A.B. Simpson – men whose lives have made spiritual history. You would like to be like them and do the things they did, and yet maybe you have never taken the trouble to find out why it was they were what they were, nor how it was they did what they did! Instead, you mobilize your own resources and seek to emulate the example they set, and are constantly buffeted by a sense of frustration because of your hopeless failure in the endeavor.
As some have sought to introduce you to the principles that made these men what they were, and enabled them to do what they did, you have been impatient, and said, “Don’t interfere! I’m too busy trying to be like them, and I don’t have time to listen to you!” Now is that not stupid? Why was Hudson Taylor what he was, and how could he do what he did? Why was A.B. Simpson what he was, and how could he do what he did? Were they God’s favorites? Of course they were not! They were simply men who had qualified in the school of failure and despair. They were men who came to the end of themselves and discovered that what they were apart from God was nothing!
Moses began by being a failure! That was the school from which he qualified! Abraham began by being a failure! That was the school from which he qualified! Jacob was a hopeless failure! David was a hopeless failure! Elijah was a hopeless failure! Isaiah was a hopeless failure and “a man of unclean lips,” but it is in the school of destitution – the bitter school of self-discovery – that finally you graduate into usefulness, when at last you finally discover the total bankruptcy of what you are apart from what God is! These men made this discovery, and were blessed.