Oct 1- Doctrine & Covenants 110:13-16

Malachi taught that without the sealing keys of the priesthood the whole earth would be wasted. And now, April 3, 1836, the day for those keys to be restored has arrived! This was the culmination of the restoration of the gospel up until that point!

Joseph Fielding Smith- Doctrines of Salvation, vol 2 page 100-101

Elder Tuttle

https://www.churchofjesuschrist.org/study/ensign/1982/05/the-first-and-the-last-words?lang=eng