The least likely to succeed = the most likely to succeed, in Jesus. One of the things the Bible is clear about regarding God choosing those He can use is that you do not have to be professional, just available. The condemning voices of the enemy are constantly trying to discourage God's people from being what God called them to be. It seems that every time God wanted to use somebody in the Scriptures, it was the most unlikely of people He used to do the most exceptional things. Perhaps the reason is because He would then truly get the glory.