Alma 17

Mormon writes that of the sons of Mosiah that had gone amongst the Lamanite that -

"...they had searched the scriptures diligently, that they might know the word of God.
3 But this is not all; they had given themselves to much prayer, and fasting; therefore they had the spirit of prophecy, and the spirit of revelation, and when they taught, they taught with power and authority of God."  (Book of Mormon | Alma 17:2 - 3)

I note that these brethren were able to preach and teach with "power" as a result of searching the scriptures diligently, and much prayer, and fasting.

Also, I note that just because they were faithful and diligent did not mean they would not experience afflictions for -

"...for they had many afflictions; they did suffer much, both in body and in mind, such as hunger, thirst and fatigue, and also much labor in the spirit."  (Book of Mormon | Alma 17:5)

Yet -

"...the Lord did visit them with his Spirit, and said unto them: Be comforted.  And they were comforted.
11 And the Lord said unto them also: Go forth among the Lamanites, thy brethren, and establish my word; yet ye shall be patient in long-suffering and afflictions, that ye may show forth good examples unto them in me, and I will make an instrument of thee in my hands unto the salvation of many souls."  (Book of Mormon | Alma 17:10 - 11)

Church service or doing the Lord's will and work was never intended to be easy.