“And God said, ‘I will be with you’”. 

Ex 3:12 NIV

Most people are ambitious. We want to get on. The fact that the higher positions usually carry better pay-packets is only one factor that motivates us to reach for them. The other is just sheer prestige – the desire to be seen, to be recognized, admired and envied. We all want to be “Number One”. 
And some channel that ambition into spiritual aspects of life as well. But the natural reaction when God calls us to some specially significant role is to recoil in fear, and to express a feeling of inadequacy. “What? Me?” we say. And indeed, what person – sinful, weak and all-too-human – is adequate for any task God calls them to? God did not contradict Moses when he confessed his sense of inadequacy. In effect he agreed with him. But he made it quite clear to Moses that it wasn’t about Moses’ capability at all. It was about the God who would be with Moses. So when the shepherd Moses responded to the God of his forefathers with his question “Who am I?” God replied with his big “But”. It wasn’t to be about Moses’ leadership strengths or weaknesses at all. The whole enterprise was to be based on faith in the God who said, “But I will be with you”. That made a huge difference. With God all things are possible. As Moses discovered . 
To feel inadequate to serve Jesus is perhaps the best qualification you can have. People who think they are the right people might just not be as right as they think they are. When you are asked, ask God to be with you and to help you. 

Lord, give me the strength I need to do the things to which you assign me.