Joseph Smith on Missionary Work

After all that has been said, the greatest and most important duty is to preach the Gospel.
Teachings of the Presidents of the Church, JS, 327

Let the Saints remember that great things depend on their individual exertion, and that they are called to be co-workers with us and the Holy Spirit in accomplishing the great work of the last days.
TPJS 178-9

Covenants

 

Heber C. Kimball

When I went into the water [of] baptism I made [a] covenant I would forsake the world with all [that] pertains to it, and cleave unto the Lord God with all my heart all my days. This is the covenant that I made, to turn away from the world. That is the covenant you made, or the one you should have made. Now, will you fulfill it?” (Oct. 7, 1853).

Dec. Ensign, 57.