This statement is so true in my life. God has placed me in positions in ministry and vocation that I didn't always feel equipped to do. Every single time, he has given me the training or tools necessary to perform the job. Even today in my current position as principal, he provides over and over again - either with people that have just the right skill to complement our ministry, training I can attend to better equip me, or opportunities to network other individuals that can provide a service we need.
There are countless examples in scripture where God takes a man (or woman) who is less than desirable or qualified by the world's standards and uses them in mighty ways.
Peter - a simple fisherman who helps found the early church
Esther - a simple Hebrew girl who becomes Queen and helps save the Hebrews from execution
Paul - a Jew who is persecuting Christian's and ends up being a missionary and spreading the gospel to other continents
David- a simple shepherd boy who defeats the mighty giant, Goliath and goes on to become King of Israel
Mary - a young girl who became the mother of God's son, Jesus
There are many more examples in scripture. I know I have always loved the story of Joseph. His brothers were jealous of him and his father's affection for Joseph. They sold him off as a slave and told their father he was dead. Joseph ended up in Egypt and in the house of Potiphar. In spite of many horrible things being done to him, he rose to a very powerful place in Egypt. God equipped him to interpret dreams. This enabled him to prepare Egypt for a devastating time of famine.Through this, he was reunited with his family and he was able to take care of them during the famine. This was all a part of God's bigger purpose and example of redeeming his people.
How has God equipped you for his purpose?