Should a church receive anyone into membership, who may not understand basic doctrines such as Calvinism or even the doctrine of the Trinity?

I would much prefer to answer this question on a case-by-case basis as it is difficult to give any hard and fast, and all-encompassing principle that can be accurately applied without specific details. Nevertheless, I think some guidelines may be helpful as this is a real life question pertaining to the local church, which we have to deal with from time to time.

I am personally convinced that church membership must not be conditioned solely on knowledge. A person who has more knowledge of divinity is not necessarily a better Christian than another who knows very little. It is a well-known fact that there are many seminary professors who know a lot about the Bible, but know not Christ. As a matter of fact, demons are likely to know much more theology than most, if not all, of us (Jas 2:19), but that does not make them Christians or disciples of Christ?

Moreover, when you examine the New Testament records, you will find that no one is ever admitted or barred from membership because of lack of knowledge. Rather, you find evidences that entire households were admitted into membership via baptism, though only the faith of the head of household was known (Acts 16:14–15; 31–33). So, although it is prudent for the church (through the elders) to examine the knowledge of everyone who applies for admission into membership (Amos 3:3—“Can two walk together, except they be agreed?”), no one should be barred from membership solely on grounds of lack of knowledge in specific areas of doctrine. Rather, if anyone, who professes Christ as Saviour and Lord, is refused admission into membership to the church, it should be on grounds of evident unregeneracy (such as blatant disregard for the Word of God, and a refusal to acknowledge sin and dependency upon Christ) in the case of adults, or hostility towards the church’s doctrine, practices and ideals. Of course, gross ignorance such as failing to believe that there is only one living and true God, and that Christ is the Son of God, and that He is the only way of salvation from sin and the wrath to come, would mean a lack of credible profession of faith and therefore disqualifies a person from being regarded as a Christian.

As the elders examine the candidates for membership (or baptism), the principle of Jude: “And of some have compassion, making a difference” (Jude 22) must always be borne in mind. The Lord has made us differently. Some of us have greater intellectual capacities and some less. We must never assume that only those who can independently enunciate all the core doctrines of Christianity are true believers. For example, I would have no difficulty receiving into membership an uneducated old lady who says, “I love the Lord Jesus Christ; I thank God He has saved me from my sin, and I want to serve Him.” Of course, from those who can say more, we should expect more. But unless we know the applicant to be an intellectual person who has strong convictions on certain points of doctrine (which may turn out to be divisive in the church), we should be satisfied with an assent on any point of doctrine raised.

Membership or Baptism, of course, should not be seen as the end of church’s obligation to the individual—as often is the case in many a church today. The church must instruct or catechise her members who may be deficient in knowledge in any way. Notice that teaching (Greek: didaskô) comes after baptising in the Lord’s great commission (Mt 28:18–20; the first word translated ‘teach’ is more properly: ‘make disciples’ [Greek:mathêteuô]). All members of the church, new or old, of course, should have covenanted to come under the authority, instruction and discipline of the leadership (e.g., session) of the church, and as such should submit cheerfully to attend any instructional lessons that the leaders may appoint.