Paul does not address this letter to a church, but to the Christians in Rome. In Scripture a Christian is always associated with the church. I believe it is assumed - the idea of a Christian who is not a member of a local church is as foreign to Scripture as it should be to us today.
Again, he illustrates the "body" of Christ by first introducing the physical human body, just as he does in 1 Cor. 12:12. The plural pronoun "we" is directly applied to that singular definite article physical body. However, no one would assume that Paul is speaking about some different kind of human body composed of all humans when he idenifies this singular body with "we" as some univeral invisible human body. No, he means "we" all have in common the same body in kind - the physical human body - and this physical human body has many members. So likewise is Christ, the body of Christ. They all shared in common the same church body IN KIND. The historical "we....us.....ye....you" in the New Testament epistles of Paul are directed toward Christians who were members of the churches Paul constituted. His prison letters were designed to be circulartory letters (Col. 4:16). As you said, "the idea of a Christian who is not a member of a local church is as foreign to Scripture as it should be to us today" as they all had in common ONE KIND of church body - the local visible congregational body of Christ.
My objection deals with Christians who assemble for the exact same purposes as a church would assemble
You are placing the cart before the horse. Christians assembling for the same purpose does not make it a NT church. In the Great Commission assembling is preceded by certain prerequisites in order to make it a NT. church.You have listed only one of those stated prerequisites - being a Christian - but that is not the only prerequisite for assembling as a NT. church..
Take note of the pronouns in the Great Commission "ye" versus "them." Who is being authorized here to administer the Great Commission? "ye" or "them"??
Now, lets identify these two groups of Christians. Let's start with "them", who are they? Those identified as "ye" had been instructed to "go" and make disciples of "the nations." Mark further defines this going (aorist tense participle in the Greek text) is with the gospel (Mk. 16:15). Hence, "them" are those out of the nations that received the gospel. They are Christians but they are not authorized to admnister any part of this commission but rather they are the recipients of this commission. They have no authority to baptize themselves or anyone else. They cannot teach what they have not been taught. They are the objects of this commission who need baptizing and instruction by "ye" (who we will idenitfy later). The aorist tense partciple (having once gone) in connection with the arorist tense verb (that literaly means "make disciples") demands that the action of going precedes the action of the verb. This is important, because it demands evangelization must occur before baptism or assembling under an instructor. Then Jesus changes to present tense participles (baptizing....teaching) which show identifical action with the main verb or this is what is inclusive of making disciples. The proper materials are evangelized people which comes first in this process of making disciples. However, making disciples is inclusive of baptizing them and then assembling them under this "ye" to learn how to observe all things commanded by Christ. There is a direct order and process in making disciples and it is followed to the tee in Acts 2:40-41 in the exact same order.
Baptism precedes assembling and baptism is the second prerequisite for assembling as a church. If you can find an unbaptized church in the NT please point it out - there are none. Why? Because it would be DISOBEDIENCE to the command of Christ (imperative mode verb) and his Great Commission process.
Now, lets turn our attention to the identification of the pronoun "ye" in this commission. Who are "ye"? In the context "ye" has for its nearest antecedent "disciples" in verse 16. Matthew did not use the term "apostles" but "disciples" and for a very good reason. Those identified as "ye" in this commission are those who "HAVE" (v. 20) already been through this threefold process. They have already been evangelized under John the Baptist (Jn. 3:36) and already "HAVE" been habitually assembling for instruction in the all things under Christ:
Acts 1:21
Therefore from these men who have accompanied us all the time that the Lord Jesus went in and out among us,
22 beginning from the baptism of John until that same day that He was taken up from us, must one be ordained to be a witness with us of His resurrection."
It takes disciples to make disciples or else the blind are leading the blind. Therefore, this "ye" are the early congregation of Christ that met for a business meeting in Acts 1 and are "all" the ones assembling on the day of Pentecost "in one accord in one place" that the 3000 evangelized were "added unto" by the very same orderly process commanded here by Christ in the Great Commission.
1. As many as received the word - evangelization "go"
2. were baptized - baptization - "baptizing"
3. added unto them - continuing stedfastly in the apostles doctrine..- conregization
So, the first two prerequisites for assembling as a NT. congregation are:
1. Christian material
2. Bapitzed Christian material
The third prerequisite is the proper administrator of baptism and assembling them for instruction - "disciples" or those who already have been through the process. They are the ONLY ones authorized to administer baptism and to assemble these baptized believers in an observing body. The blind cannot lead the blind! Can anything clean come out of an unclean thing? No, and no one who has not been taught cannot teach others.
What is a "disciple"? (1) One who has already been through this process; (2) one who administers the SAME gospel as Christ commanded; (2) One who administers the SAME baptism Christ commanded; (3) One who teaches the same faith and order Christ commanded. A "disciple" is a FOLLOWER of Christ in this same threefold process. This is why all churches in the New Testament were founded upon the SAME FAITH AND ORDER.
A person who does not go with the SAME gospel as Christ commanded is not authorized by Christ to administer this commission as that is "another gospel". - Gal. 1:8-9
A person who does not administer the SAME baptism as Christ commanded is not authorized by Christ to administer this commission as that is rejecting "the counsel of God" - Lk. 7:29-30
A persons who does not teach the SAME faith and order as Christ commanded is not authorized to administer this commission as that is "departing from the faith" once delivered - 1 Tim. 4:1;
The Great Commission is a command to reproduce disciples of like faith and order or they are not really disciples (followers) of Christ (Acts 20:29-30). Those who depart from this process is where denominational originated (Acts 20:29-30).
Churches do not just happen by beleivers just coincidently meeting together but a church is "made" through the Great Commission process under the authority of a previous plural "ye" of like faith and order.
1. Where there are no professed born again beleivers in the gospel there can be no true church of Christ.
2. Where there is no scriptural baptism there can be no true church of Christ
3. Where there is no one to instruct baptized believers how to observe all things commanded there is no true church of Christ as the blind cannot lead the blind.
Therefore, the qualification to assemble as a NT church must originate under the authorized "ye" of the Great Commission, which is preceding church of like faith and order wherein newly baptized believers are merely "added unto" (Acts 2:40-41) OR by church sent missionaries who preach the SAME gospel, administer the SAME baptism and teach the SAME faith and order thus constituting the SAME kind of church - the NT. kind (Acts 13:1-4).
but are not considered a "real church" because they misunderstand how God effected salvation.[/QUOTE)
No, not because they "misunderstand" but because they DENY eternal life, deny the sufficiency and efficiency of the Christ. For example, a person may be saved and not "understand" the true God. However, no person can be saved who DENIES the true God (Jn. 17:3).
How do you know they are saved. Denial of eternal life is an indication they
may not be saved. It is absurd to fashion your argument like this because YOU DO NOT KNOW. There are true Christians in the Roman Catholic church but that does not make them a true Church of Christ.