I took the time to read through this thread from beginning to end. I do believe that the man of God needs only the scriptures to be THROUGHLY (thoroughly) furnished in regard to doctrine, instruction, correction and reproof for sufficieny in all good works.
There are three problems with secular Church History:
1. It is not inspired and therefore subject to the limitations and bias of the historian
2. Incomplete and thus lacking in full perspective (which often means distortion)
3. Often inaccurate due to bias, intential misrepresentation, intential revision of history
Is history valuable? Yes, but with many limitations.
I do believe the best commentary on the scriptuers is the scriptures and the best interpreter of the scriptures is the Holy Spirit.
The Great Commission is an age long commission requiring organic succession between discipler and disciple. For example, for the greater part of history between the first century and the present, one must actually "go" to those whom he presents the gospel. For example, it is impossible to administer baptism without organic contact between the administrator and the candiate for baptism. For example, it is impossible to teach others to obey all things Christ commanded without organically assemblying together with them over a period of time.
Another fact of the Great Commission is that it was given only to those who had previously experienced this organic hands on process being spelled out. For example, Jesus said, "whatsoever I HAVE commanded you." The blind cannot lead the blind nor did Jesus commission the ungosplized to gospelize themselves nor could the untaught teach others what they have not been taught.
There are three categories of people found in the Great commission as given in Matthew 28:19-20. There are those being commissioned identified as "ye." There are those they are sent unto "all nations." There are those out of all nations that receive the gospel unto which they are to administer baptism and teach how to observer all things "them."
The Great Commission was never given to "all nations."
The Great commission was never given to "them"
The Great commission was only given to "ye" or previous baptized believers who had been taught how to observe all things as Christ commanded. The very meaning of "make disciples" denies they are to inovate they own doctrine and practice but are to be "followers" of anothers.
Christ never authorized or commissioned anyone to go preach "another gospel" as any other is accursed (Gal. 1:8-9; 2 Cor. 11:4).
Christ never authorized or commissioned anyone to administer another kind of baptism than what he himself submitted to and administered to others.
Christ never authorized or commissioned anyone to teach others to observe another faith and practice as that is what the New Testament defines as apostasy or departure from the faith once delivered.
The Bible does not give direct authority from God to the reader to administer the great Commission. If that were true, the "all nations" or "them" could equally adminsiter it as "ye."
No one is authorized to make disciples for Christ but the "ye" who has already been discipled in the SAME gospel, SAME baptism and SAME faith and practice as commissioned by Christ as that is the only possible way a person can be discipled in the "all things" that Christ commanded and be his disciple or be a follower of him in the gospel OF Christ and the baptism OF Christ and the doctrine and practice OF Christ.
Neither did Christ authorize anyone to depart from this commission as given or to make disciples according to their own idea.
Matthew identify the contextual great commission "ye" or "you" as "disciples" (v. 17). Only "disciples" can make "disciples" and disciples are characterized by these three distinctives - the same Gospel of Christ, the same baptism of Christ and the same faith and order of Christ.