Alma 14

Merriam-Webster's Dictionary defines long-suffering as -

"suffering for a long time without complaining : very patient during difficult times"

And can't imagine a greater example of long-suffering or as I might say, "patience in affliction", as that of Alma and Amulek amongst the wicked leaders of Ammonihah.  The readers would have to read the entire chapters of 14 & 15 in the book of Alma.  But I will mentioned as they brought to the place of martyrdom where women and children were being consumed by fire, when -

"...Amulek saw the pains of the women and children who were consuming in the fire, he also was pained; and he said unto Alma: How can we witness this awful scene?  Therefore let us stretch forth our hands, and exercise the power of God which is in us, and save them from the flames.
11 But Alma said unto him: The Spirit constraineth me that I must not stretch forth mine hand; for behold the Lord receiveth them up unto himself, in glory; and he doth suffer that they may do this thing, or that the people may do this thing unto them, according to the hardness of their hearts, that the judgments which he shall exercise upon them in his wrath may be just; and the blood of the innocent shall stand as a witness against them, yea, and cry mightily against them at the last day."  (Book of Mormon | Alma 14:10 - 11)

It is amazing how the Lord allows agency to the destruction of many.  It would be interesting to count the number of times Alam and Amulek were "smote" in the face.  Mormon records much of this afflictions but also mentions -

"...many such things, yea, all manner of such things did they say unto them; and thus they did mock them for many days.  And they did withhold food from them that they might hunger, and water that they might thirst; and they also did take from them their clothes that they were naked; and thus they were bound with strong cords, and confined in prison."  (Book of Mormon | Alma 14:22)

No question this was long-suffering.  We are taught -

"No power or influence can or ought to be maintained by virtue of the priesthood, only by persuasion, by long-suffering, by gentleness and meekness, and by love unfeigned..."  (Doctrine and Covenants | Section 121:41)

Long-suffering and patience in affliction is part of our priesthood virtues.