Should Christians cooperate with those with whom they disagree theologically?
First things first. There’s no true unity except in the truth. Therefore, all Christian cooperation must be based on doctrinal agreement. The question is then, how much? Do Christians need to agree about every nuance of every doctrine—or the interpretation of every single passage of Scripture—in order to work together?
The answer must be no. Paul was willing to continue his partnership with the Philippians even if they didn’t see eye to eye on absolutely everything (Phil. 3:15). Moreover, the New Testament’s repeated exhortations to Christian unity (John 17:20-26; Eph. 4:3; Phil. 2:1-2) force us to recognize that we must work together with Christians with whom we disagree theologically.
If we only cooperate with those Christians with whom we agree over every single doctrine, then we will cut ourselves off from other Christians as we create an increasingly small circle of fellowship until it is finally a fellowship of one.
The question, therefore, is not, should Christians cooperate with others with whom they disagree theologically, but how much theological agreement should they require for various levels of cooperation, such as being members of the same church, or pooling resources to send missionaries to a foreign country, or publishing books together. Different kinds of Christian cooperation will require different levels of agreement.