"And [Jesus] withdrew from them about a stone's throw, and knelt down and prayed, saying, 'Father, if you are willing, remove this cup from me. Nevertheless, not my will, but yours, be done.' And there appeared to him an angel from heaven, strengthening him." — Luke 22:43, ESV
What was that angel thinking? What was going through the mind of that one angel who had been given the ministry to strengthen the Almighty One? In heaven, we do not get a picture of angels worshipping God so that God is strengthened. Rather, we see angels worshipping God because he is all strength. So what was this angel thinking? Was he nervous? Did he seem inexperienced for the task set before him, to minister to God? He had not been "trained" for this, but he had been sent for this very purpose.
And yet the very same thing is true of us. We are trained for what we are called to do for Jesus. For those of you who read that last sentence and disagree, that is proof that you have grown to rely on your own "abilities" rather than on Jesus. I am not trained for the supernatural. Before God calls me to the miraculous and supernatural tasks that he has for me to do, I'm not trained. However, because I have experienced the miraculous of Jesus (namely, experiencing his salvation), I have a glimpse into the miraculous. But trained? No. And honestly, its better that way.
If you feel inadequate for the task that God has for you, good. You can be sure if you feel inadequate that it is truly Jesus that has called you to it. If you feel adequate, either it wasn't Jesus who called you to it or you actually think that you are his peer. Either way you're in a bad place. It truly is better to feel inadequate and see Jesus accomplish the miraculous through you than to feel adequate and left to "accomplish" the ordinary, building your own kingdom of sand rather than being used for the kingdom of God.