Soul winning is not accomplished by stealing members from already-established churches, just to train them to utter our peculiar pronunciation of Shibbolet (Judges 12:4-6). Instead, soul winning means bringing souls to Christ rather than making converts to our assembly.
Sheep-stealers beyond the walls of the church are not acting in a brotherly fashion...The increase of God’s kingdom should be desired more than the growth of a sect. It would be a great trade to make a Paedo-Baptist brother into a Baptist, because we value our Lord’s ordinances. But rather, we should labor earnestly to raise a believer in salvation by free-will into a believer in salvation by grace, because we long to see all spiritual teaching built upon the solid rock of truth and not upon the sand of imagination.
At the same time, our far-reaching objective isn’t the revision of opinions but the regeneration of natures. We long to bring men to Christ and not to our own peculiar views of Christianity. Our first concern must be that the sheep are gathered to the great Shepherd...By all means let us bring true converts into the church, for it’s a part of our work to teach them to observe all things Christ has commanded. However, this is to be done to make true disciples and not Christians in word only. If we aren’t careful to obey in this matter, we may do more harm than good at this point.
Adapted from The Soul Winner by Charles Spurgeon