Mosiah 13

Abinadi confirms that  after ancient writings went -

"...forth by the hand of the twelve apostles of the Lamb, from the Jews unto the Gentiles, thou seest the formation of that great and abominable church, which is most abominable above all other churches; for behold, they have taken away from the gospel of the Lamb many parts which are plain and most precious; and also many covenants of the Lord have they taken away."  (Book of Mormon | 1 Nephi 13:26)

He does this as he asks Noah and his wicked priests concerning the coming of Christ -

"...did not Moses prophesy unto them concerning the coming of the Messiah, and that God should redeem his people?  Yea, and even all the prophets who have prophesied ever since the world began—have they not spoken more or less concerning these things?"  (Book of Mormon | Mosiah 13:33)

Obviously many plain and precious parts of scripture including covenants were taken away or lost.