We are here informed that this book, as it came from the mouth of the Jew, contained the same gospel of the Lord of which the Apostles bear record That is to say, the prophecies and the rites, the clothes, the buildings, the sacrifices, all were typical of the plan of salvation which became a reality in the life, the teachings, the death, and glorification of our Lord, as recorded in the New Testament. The Apostle Paul, in the letter to the Hebrews, makes this very clear.
But after this book, together with the record of the Apostles, goes forth "by the hand [not mouth] of the Apostles" (v. 26), then the ecclesiastical organization comes into existence, which has "taken away from the gospel of the Lamb many parts which are plain and most precious." (v. 26) The object of this mutilation is stated in verse 27.