Anyone who has been involved in pastoral ministry for any length of time, will likely have come across this situation where a Christian has decided to marry a non-believer. Personally, I find it hard, no-one wants to have a painful conversation and point out to friends that a course of action will lead to disobedience and likely heartache. Who wants to do that? But those conversations must be had. Anyway I found this by Kathy Keller and I think she hits the nail on the head.
“Having grown weary and impatient, I want to snap and say, “It won’t work, not in the long run. Marriage is hard enough when you have two believers who are completely in harmony spiritually. Just spare yourself the heartache and get over it.” Yet such harshness is neither in line with the gentleness of Christ, nor convincing.”