It is one thing to join the church externally, and it is another thing to speak of an external church. Even though they [i.e., unconverted persons] are externally in the church, this does not mean that there is an external church of which they are bonafide members. Membership in an external church to which the promise of salvation is not annexed is not their objective, but rather a church as being a fellowship within which they may be saved. To this church they apply themselves, but only externally, and not in truth with a converted and believing heart. Therefore they are no members, even though men view them as such externally. They are thus within the church as a poisonous fruit which is attached to a good tree with good fruits. They are therefore within the church as strangers, who for some time dwell in a house, but whom no one deems to be family members. Because of this external association with the church there is also an external relationship to the Lord Jesus as King of His church, as well as her true members, and they enjoy the external privileges of the church. Their entrance into the church, and the church’s acceptance of them does not make them true members of the church. Such can only come about by faith and repentance.

WILHELMUS À BRAKEL, THE CHRISTIAN’S REASONABLE SERVICE, VOL. 2, 13.