Doctrine & Covenants 84:19-21

And this greater priesthood administereth the gospel and holdeth the key of the mysteries of the kingdom, even the key of the knowledge of God.
Therefore, in the ordinances thereof, the power of godliness is manifest.
And without the ordinances thereof, and the authority of the priesthood, the power of godliness is not manifest unto men in the flesh;
Doctrine & Covenants 84:19-21

Read in scriptures: http://bit.ly/2aJJGgp