Most of us are in relatively small congregations. I sure am.
And while we pay lip service to avoiding sheep stealing, the reality is that in any small congregation (big ones, too, for that matter), our hearts flutter a little when a visitor arrives. Especially a local visitor.
Why's that? Well, the best construction is that we want to fulfill our Lord's command, that we want to preach the gospel to all nations, that we want to bring the good news of salvation to all.
And most congregations genuinely want that. The question is why we get such joy when someone arrives who is a baptized Christian, someone who has heard and trusts the gospel. And the reality is that our reaction is sometimes a selfish one.
Selfish because a newcomer is another potential giver, who will help out with the perennial money problems. Or someone else who might teach Sunday school, help out with VBS, whatever.
It's not wrong to rejoice when someone uses their gifts and talents in God's service. That's a good thing, and there is genuine joy in service to God.
The problem arises when we are too quick to take on a newcomer, someone who might be coming to us because of a conflict at another congregation, someone who might be angry with their pastor or someone who's just tired or bored with their church, and we offer a change.
I think pastors need to be sensitive to this. Because people will not tell all the details. They will flatter a new congregation, telling them that they are better, more faithful, whatever. It's good to probe a bit. And if there's anger, if there's bitterness, if there's unforgiveness back at the old church, that person needs to get it resolved. I'm not saying they should be discouraged from joining. But joining without resolving the old conflict only guarantees that the old wound will fester and become infected.
Encourage anyone in such a situation to forgive, and receive forgiveness, and ponder whether they really need to leave. If they really do need to move on, receive them joyfully. But part of confessing the church means that we respect and love our brothers, even if they have done this person wrong. It doesn't mean condoning wrongdoing, but we are one with our brethren. And this is part of acknowledging that brotherhood.