Mormon 1 - 4

As Mormon begins his own record, he tells us that -

"...I, being fifteen years of age and being somewhat of a sober mind, therefore I was visited of the Lord, and tasted and knew of the goodness of Jesus..." (Book of Mormon Mormon 1:15)

But he also tells us that during this period, as he was tasting of the goodness of Jesus, -

"...wickedness did prevail upon the face of the whole land, insomuch that the Lord did take away his beloved disciples, and the work of miracles and of healing did cease because of the iniquity of the people.
14 And there were no gifts from the Lord, and the Holy Ghost did not come upon any, because of their wickedness and unbelief." (Book of Mormon Mormon 1:13 - 14)

Mormon doesn't necessarily say much on the matter, but it would be hard for me to believe that Mormon, who was named after his father, would have had such a "sober mind" at such a young age without the great influence of some righteous parents. I tend also to assume that he was raised in a home of a military leader and must have received some kind of training in that -

"...notwithstanding I being young, was large in stature; therefore the people of Nephi appointed me that I should be their leader, or the leader of their armies.
2 Therefore it came to pass that in my sixteenth year I did go forth at the head of an army of the Nephites..." (Book of Mormon Mormon 2:1 - 2)

At the age of 11 his father takes him to Zarahemla where Mormon witnesses a war between the Lamanites and the Nephites. Whether this is the first, it doesn't say, but from then to the end of his life, he witnesses continuous death and destruction in that -

"...it is impossible for the tongue to describe, or for man to write a perfect description of the horrible scene of the blood and carnage which was among the people, both of the Nephites and of the Lamanites; and every heart was hardened, so that they delighted in the shedding of blood continually." (Book of Mormon Mormon 4:11)

And that the period of his life when -

"...there never had been so great wickedness among all the children of Lehi, nor even among all the house of Israel, according to the words of the Lord, as was among this people." (Book of Mormon Mormon 4:12)

You can't read these verses without having great compassion for Mormon. Yet, while living through this great wickedness, carnage, and death, he never faultered. We know that during his life he possessed the record or Nephi and the words of Christ for at a young age, Ammoron -

"...he came unto me, (I being about ten years of age, and I began to be learned somewhat after the manner of the learning of my people) and Ammaron said unto me: I perceive that thou art a sober child, and art quick to observe;
3 Therefore, when ye are about twenty and four years old I would that ye should remember the things that ye have observed concerning this people; and when ye are of that age go to the land Antum, unto a hill which shall be called Shim; and there have I deposited unto the Lord all the sacred engravings concerning this people.
4 And behold, ye shall take the plates of Nephi unto yourself, and the remainder shall ye leave in the place where they are; and ye shall engrave on the plates of Nephi all the things that ye have observed concerning this people." (Book of Mormon Mormon 1:2 - 4)

And it was his study of these records that contributed so much to Mormon's faithfulness for he tells us -

"..I searched among the records which had been delivered into my hands, and I found these plates, which contained this small account of the prophets, from Jacob down to the reign of this king Benjamin, and also many of the words of Nephi.
4 And the things which are upon these plates pleasing me, because of the prophecies of the coming of Christ; and my fathers knowing that many of them have been fulfilled; yea, and I also know that as many things as have been prophesied concerning us down to this day have been fulfilled, and as many as go beyond this day must surely come to pass—" (Book of Mormon Words of Mormon 1:3 - 4)

And -

"...I shall take these plates, which contain these prophesyings and revelations, and put them with the remainder of my record, for they are choice unto me..." (Book of Mormon Words of Mormon 1:6)

It is apparent that Mormon had the words of Christ, he searched and studied them, and because of his obedience and righteous desires, they were pleasing and choice unto him.