Westminster Confession of Faith
Chapter 24: Of Marriage and Divorce
3: It is lawful for all sorts of people to marry, who are able with judgment to give their consent.[478] Yet it is the duty of Christians to marry only in the Lord.[479] And therefore such as profess the true reformed religion should not marry with infidels, papists, or other idolaters: neither should such as are godly be unequally yoked, by marrying with such as are notoriously wicked in their life, or maintain damnable heresies.[480]
Snyder's Soapbox 