The book of Acts deals with the work of the early church in spreading the Gospel from Jerusalem to 'all the ends of the world'. It is amazing that God chose these men, who in the Gospels, were so foolish and narrow-visioned at times. God used men who were prideful, self-centered, unfaithful (at times), and bigoted to 'turn the world upside down'!
This should give aspiring Gospel preachers hope. The Gospels' description of the disciples should be a mirror into our own lack of personal ability (but with Him, all things are possible). We also need to remember that the disciples became the Apostles. The old cliche is that God equips the called, not calls the equipped. He will prepare and secure the needed gifts and abilities. The world still has plenty of places that need to be 'turned upside down' for the sake of Christ and his Gospel. Proclaim to the world that there is another king- Jesus Christ! This is our calling.