I have a Christian friend who recently asked around for a dentist, but specifically a Christian dentist.
I understand the intent, but it's a platitude we Christians should not employ. Does a Christian do a better job of cleaning your teeth? What about Christian car dealers and lawyers, both of whom have to put some ethics on the side to just maintain a proper business.
I think the attitude of many Christians is to blindly accept people who say they are Christian first. This is a little isolationist and I think in our free-market culture it leads to big business in the name of Christ. Choosing to purchase goods and services from other Christians because they are Christians is not Christ’s example. Christ cleared out the temple because the people inside professed themselves to be Jews but were Judaizers who used the faith of followers to sell their goods.
Furthermore, I think it’s actually a little bit selfish. If you think about it, we want to believe that because a person is a Christian that he/she is going to do a much better job; however, Christians are not perfect--not in this life, anyways. So, what happens when they do an imperfect job, does that mean the may not be a true Christian? What if someone who isn't a Christian does a much better job and even charges less, could that person be a Christian? People search for Christian sales/servicepeople because it benefits them. The truth of the matter is we should be focused on demonstrating ourselves as salt of the earth that incites the unregenerate to look inwardly and try their own hearts.
FWIW, I’m not saying it's wrong to have a Christian dentist at all, but it irks me when Christians isolate themselves to Christians as the source of goods and services. I pray that when one searches for a dentist, a car dealer, a lawyer, or whatever occupation, that they find the person to be excellent, first, and even still I hope the person is a Christian; but I pray he/she is a Christian for his/her own sake, not as much for it.