By the mouth of holy prophets

1. Luke 1: 70
     70 As he spake by the mouth of his holy prophets, which have been since the world began:
2. 2 Ne. 9: 2
     2 That he has spoken unto the Jews, by the mouth of his holy prophets, even from the beginning down, from generation to generation, until the time comes that they shall be restored to the true church and fold of God; when they shall be gathered home to the lands of their inheritance, and shall be established in all their lands of promise.
3. Mosiah 18: 19
     19 And he commanded them that they should teach nothing save it were the things which he had taught, and which had been spoken by the mouth of the holy prophets.
4. 3 Ne. 1: 13
     13 Lift up your head and be of good cheer; for behold, the time is at hand, and on this night shall the sign be given, and on the morrow come I into the world, to show unto the world that I will fulfil all that which I have caused to be spoken by the mouth of my holy prophets.