That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled, concerning the Word of life ... That which we have seen and heard declare we unto you, that ye also may have fellowship with us: and truly our fellowship is with the Father, and with his Son Jesus Christ. [1 John 1:1-3 KJV]
Towards the end of the first century, John the apostle, now an aged man, as heresies and schism began to grow in the early church, rather than 'go forward' to 'further revelation' seeks to re-establish the church as to 'that which was from the beginning'.
The early church was established on nothing other than 'Jesus Christ and him crucified', 1 Corinthians 2:2 : his birth, his baptism, his temptation, his ministry, his transfiguration, his entry into Jerusalem, his sufferings, his death, his bloodshed, his resurrection, his ascension and his enthronement : twelve essentials of the New Testament.
Nothing remained other than to 'hold fast the form of sound words', 2 Timothy 1:13, in the kingdom of God, Colossians 4:11, and to 'wait for His Son from heaven', 1 Thessaloninans 1:10, to return 'in like manner as ye have seen him go into heaven', Acts 1:11.
John's message is to hold that which was from the beginning, not to expect, seek, follow after . . . something new. John had already given further revelation, but it was information about what would shortly come to pass, Revelation 1:1, during the Church age.
It was not a new gospel. Thus, in regard to doctrine, conduct, church practice and church government : he refers them back to 'that which was from the beginning'.
Thus was the Reformation. Not a 'further revelation' but a return to that which was from the beginning. A return to the scripture. A return to simplicity. A return to justification by faith. A return to a scriptural form of church government and Christian conduct.
What denominations (within the sphere of Trinitarian, Protestant, Reformed and Baptist profession) confess, publicly, that this is what they do, particularly in times of declension, of backsliding, of confusion, of failure : rather than look forward to a 'further revelation', look back to 'that which was from the beginning' and seek to be re-established on that sure - that apostolic - foundation ?