Why Don't Christians Preach the Gospel to Outsiders?

 The following poignant observation is from Roland Allen's book Missionary Methods:  St. Paul's or Ours:

 "Christians receive the Spirit of Jesus, and the Spirit of Jesus is the missionary spirit, the Spirit of Him Who came into the world to bring back lost souls to the Father. Naturally when they receive that Spirit they begin to seek to bring back others, even as He did.

"The reason of our failure is, I believe, largely due to the fact that we quench that Spirit. We educate our converts to think, as we, accustomed to a long-established and highly organized Church, naturally think, that none but duly appointed ministers may preach. We dread the possible mistakes of individual zeal.

"The result is that our converts hesitate to speak of religion to others. They throw the responsibility upon the licensed evangelist and 'the mission.' They do not feel any responsibility themselves to evangelize the world. Their mouths are closed. Here and there, of course, we find a man so full of the Spirit of the Lord that he cannot hold his peace, but he is a rare exception.

"We need to begin again to teach ourselves and our people what Spirit we are of, and to give liberty that the word of the Lord may have free course. When we do that, the Church will again reveal itself in its true character and become self-propagating."