Alma 13:26 - 13:31
Alma 13:26 And it shall be made known unto just and holy men, by the mouth of angels, at the time of his coming, that the words of our fathers may be fulfilled, according to that which they have spoken concerning him, which was according to the spirit of prophecy which was in them.
And when the Messiah comes, it will be made known to the prophets and other righteous individuals that he has come and has accomplish very thing that the prophets in the past said He would do which was revealed to him by revelation.
People had to be told why the destruction chronicled in third Nephi took place. That is was in fulfillment of prophecy as mentioned by Nephi and others.
Alma 13:27 And now, my brethren, I wish from the inmost part of my heart, yea, with great anxiety even unto pain, that ye would hearken unto my words, and cast off your sins, and not procrastinate the day of your repentance;
Alma now pleads with all the intensity of his own soul that the people of Ammonihah repent of their sins before it is too late. He is so worried about them that his soul actually aches to the point of feeling pain.
Probably like the pains suffered by Christ in the Garden, but of course by a far lesser degree.
Alma 13:28 But that ye would humble yourselves before the Lord, and call on his holy name, and watch and pray continually, that ye may not be tempted above that which ye can bear, and thus be led by the Holy Spirit, becoming humble, meek, submissive, patient, full of love and all long-suffering;
Alma gives them the traits that they need to have to stave off the coming disaster. They need to pray for instruction as to what to do to not be destroyed. They need to be ready to obey that instruction they receive. They need to be ready to make whatever changes they need to made to feel comfortable in God’s presence.
Alma 13:29 Having faith on the Lord; having a hope that ye shall receive eternal life; having the love of God always in your hearts, that ye may be lifted up at the last day and enter into his rest.
They need to live so that they can know that they have the real possibility of eternal life. They need to have the same love God has for them for all those around them. Again these changes are required if they want to feel at home when they meet their God again at judgment day.
Alma 13:30 And may the Lord grant unto you repentance, that ye may not bring down his wrath upon you, that ye may not be bound down by the chains of hell, that ye may not suffer the second death.
Alma wants them to make these changes in order to stave off the destruction that is sure to come if they do not repent. And if they do not repent they will suffer the permanent separation of themselves from God or the second death.Alma
Alma 13:31 And Alma spake many more words unto the people, which are not written in this book.
Alma said a lot more to the people of Ammonihah, but a portion is in the Book of Alma as edited by Mormon.