Jacob 1:18 For I, Jacob, and my brother Joseph had been consecrated priests and teachers of this people, by the hand of Nephi.
19 And we did magnify our office unto the Lord, taking upon us the responsibility, answering the sins of the people upon our own heads if we did not teach them the word of God with all diligence; wherefore, by laboring with our might their blood might not come upon our garments; otherwise their blood would come upon our garments, and we would not be found spotless at the last day.

D&C 20:46 The priest’s duty is to preach, teach, expound, exhort…
53 The teacher’s duty is to watch over the church always, and be with and strengthen them…
59 They are, however, to warn, expound, exhort, and teach, and invite all to come unto Christ…

D&C 123:13 Therefore, that we should waste and wear out our lives in bringing to light all the hidden things of darkness, wherein we know them; and they are truly manifest from heaven—
14 These should then be attended to with great earnestness.
15 Let no man count them as small things; for there is much which lieth in futurity, pertaining to the saints, which depends upon these things.