Alma 23 - 29

Alma, son of Alma, was at one time -

"...a very wicked and an idolatrous man. And he was a man of many words, and did speak much flattery to the people; therefore he led many of the people to do after the manner of his iniquities.
9 And he became a great hinderment to the prosperity of the church of God; stealing away the hearts of the people; causing much dissension among the people; giving a chance for the enemy of God to exercise his power over them... for he did go about secretly with the sons of Mosiah seeking to destroy the church, and to lead astray the people of the Lord..." (Book of Mormon Mosiah 27:8 - 10)

Ammon, one of the sons of Mosiah, recalled to his brothers Aaron, Omner, and Himni that they had at one time gone -

"...forth even in wrath, with mighty threatenings to destroy his church." (Book of Mormon Alma 26:18)

But after their marvelous conversion, Alma and the sons of Mosiah became five of the most renown missionaries of scriptural record. Alma, being ordained the presiding high priest over the Church, proselyted in many Nephite cities and villages including to the wicked and hard-hearted people of Ammonihah. Ammon and his brethren spent fourteen years of missionary service amongst the Lamanites, a "stiffnecked" people. For as Ammon recalls -

...whose hearts delight in the shedding of blood; whose days have been spent in the grossest iniquity; whose ways have been the ways of a transgressor from the beginning?" (Book of Mormon Alma 26:24)

Who -

"...have taught their children that they should hate [the Nephites], and that they should murder them, and that they should rob and plunder them, and do all they could to destroy them; therefore they have an eternal hatred towards the children of Nephi.
(Book of Mormon Mosiah 10:17)

After having great success, both Ammon and Alma share their thoughts and feelings of their missionary service.

As the sons of Mosiah returned from their mission amongst the Lamanites, Ammon is overwhelmed with emotion and expresses to his companions -

"...My brothers and my brethren...how great reason have we to rejoice; for...how many of them are brought to behold the marvelous light of God!" (Book of Mormon Alma 26:1 - 3)

"Behold, thousands of them...have been brought into the fold of God." (Book of Mormon Alma 26:4)

"...And this is the blessing which hath been bestowed upon us, that we have been made instruments in the hands of God to bring about this great work." (Book of Mormon Alma 26:3)

Aaron becomes somewhat concerned and rebukes Ammon saying -

"...I fear that thy joy doth carry thee away unto boasting...." (Book of Mormon Alma 26:10)

To which Ammon lovingly responds -

"...I do not boast in my own strength, nor in my own wisdom...I know that I am nothing; as to my strength I am weak; therefore I will not boast of myself, but I will boast of my God, for in his strength I can do all things; yea, behold, many mighty miracles we have wrought in this land...and they are brought to sing redeeming love, and this because of the power of his word which is in us, yea, and we have been instruments in his hands of doing this great and marvelous work." (Book of Mormon Alma 26:11 - 15)

And then with much emotion, Ammon expresses -

"...my joy is full, yea, my heart is brim with joy, and I will rejoice in my God... many thousands of our brethren [have been]brought to sing redeeming love...therefore have we not great reason to rejoice?
14 Yea, we have reason to praise him forever, for he is the Most High God...Therefore, let us glory, yea, we will glory in the Lord; yea, we will rejoice, for our joy is full; yea, we will praise our God forever. Behold, who can glory too much in the Lord? Yea, who can say too much of his great power, and of his mercy, and of his long-suffering towards the children of men? Behold, I say unto you, I cannot say the smallest part which I feel." (Book of Mormon Alma 26:11 - 16)

Ammon then teaches a great doctrine -

"...my brethren, what natural man is there that knoweth these things? I say unto you, there is none that knoweth these things, save it be the penitent.
22 Yea, he that repenteth and exerciseth faith, and bringeth forth good works, and prayeth continually without ceasing—unto such it is given to know the mysteries of God; yea, unto such it shall be given to reveal things which never have been revealed..." (Book of Mormon Alma 26:21 - 22)

Ammon ends with this testimony -

"...Now my brethren, we see that God is mindful of every people, whatsoever land they may be in; yea, he numbereth his people, and his bowels of mercy are over all the earth. Now this is my joy, and my great thanksgiving; yea, and I will give thanks unto my God forever." (Book of Mormon Alma 26:37)

Alma expresses his great missionary desire with -

"O THAT I were an angel, and could have the wish of mine heart, that I might go forth and speak with the trump of God, with a voice to shake the earth, and cry repentance unto every people!
2 Yea, I would declare unto every soul, as with the voice of thunder, repentance and the plan of redemption, that they should repent and come unto our God, that there might not be more sorrow upon all the face of the earth." (Book of Mormon Alma 29:1 - 2)

And then with humility follows -

"But behold, I am a man, and do sin in my wish; for I ought to be content with the things which the Lord hath allotted unto me.
4 I ought not to harrow up in my desires, the firm decree of a just God, for I know that he granteth unto men according to their desire, whether it be unto death or unto life; yea, I know that he allotteth unto men, yea, decreeth unto them decrees which are unalterable, according to their wills, whether they be unto salvation or unto destruction." (Book of Mormon Alma 29:3 - 4)

"Now, seeing that I know these things, why should I desire more than to perform the work to which I have been called?
7 Why should I desire that I were an angel, that I could speak unto all the ends of the earth?" (Book of Mormon Alma 29:6 - 7)

And very much like Ammon, Alma expresses -

"I know that which the Lord hath commanded me, and I glory in it. I do not glory of myself, but I glory in that which the Lord hath commanded me; yea, and this is my glory, that perhaps I may be an instrument in the hands of God to bring some soul to repentance; and this is my joy." (Book of Mormon Alma 29:9)

In modern day, just like Alma and Ammon, the Lord has promised to all who are called to preach -

"Wherefore, you are called to cry repentance unto this people.
15 And if it so be that you should labor all your days in crying repentance unto this people, and bring, save it be one soul unto me, how great shall be your joy with him in the kingdom of my Father!
16 And now, if your joy will be great with one soul that you have brought unto me into the kingdom of my Father, how great will be your joy if you should bring many souls unto me!"..(Doctrine and Covenants Section 18:14 - 16)