Alma's words to his sons, Helaman and Shiblon

Alma 36 and Alma 38 contain Alma's words to his sons, Helaman and Shiblon, respectively. The similarities between the beginning of these chapters is striking.
In Alma 36:1-5, we read

1 My son, give ear to my words; for I swear unto you, that inasmuch as ye shall keep the commandments of God ye shall prosper in the land.

2 I would that ye should do as I have done, in remembering the captivity of our fathers; for they were in bondage, and none could deliver them except it was the God of Abraham, and the God of Isaac, and the God of Jacob; and he surely did deliver them in their afflictions.

3 And now, O my son Helaman, behold, thou art in thy youth, and therefore, I beseech of thee that thou wilt hear my words and learn of me; for I do know that whosoever shall put their trust in God shall be supported in their trials, and their troubles, and their afflictions, and shall be lifted up at the last day.

4 And I would not that ye think that I know of myself—not of the temporal but of the spiritual, not of the carnal mind but of God.

5 Now, behold, I say unto you, if I had not been born of God I should not have known these things; but God has, by the mouth of his holy angel, made these things known unto me, not of any worthiness of myself;

In Alma 38:1-6, we read

1 My son, give ear to my words, for I say unto you, even as I said unto Helaman, that inasmuch as ye shall keep the commandments of God ye shall prosper in the land; and inasmuch as ye will not keep the commandments of God ye shall be cut off from his presence.

2 And now, my son, I trust that I shall have great joy in you, because of your steadiness and your faithfulness unto God; for as you have commenced in your youth to look to the Lord your God, even so I hope that you will continue in keeping his commandments; for blessed is he that endureth to the end.

3 I say unto you, my son, that I have had great joy in thee already, because of thy faithfulness and thy diligence, and thy patience and thy long-suffering among the people of the Zoramites.

4 For I know that thou wast in bonds; yea, and I also know that thou wast stoned for the word’s sake; and thou didst bear all these things with patience because the Lord was with thee; and now thou knowest that the Lord did deliver thee.

5 And now my son, Shiblon, I would that ye should remember, that as much as ye shall put your trust in God even so much ye shall be delivered out of your trials, and your troubles, and your afflictions, and ye shall be lifted up at the last day.

6 Now, my son, I would not that ye should think that I know these things of myself, but it is the Spirit of God which is in me which maketh these things known unto me; for if I had not been born of God I should not have known these things.

Obviously, Alma is giving his two sons the same message. But there is one exception marked with green. He asks Helaman to remember the captivity of his fathers. But he asks Shiblon to remember his own captivity. This is consistent with Alma 31:7

Now the eldest of his sons he took not with him, and his name was Helaman; but the names of those whom he took with him were Shiblon and Corianton; and these are the names of those who went with him among the Zoramites

In other words, Helaman did not have personal experience with captivity or bondage for the sake of the word, so Alma asks him to remember the captivity of his fathers. Shiblon was with Alma on his mission to the Zoramites and experienced his own bondage, so Alma asks him to remember that. That makes sense.

Then, as we know Alma goes on to relate his own experience with the angel and his repentance, in a beautiful chiasmus in Alma 36. In Alma 38:7-8, we read the abbreviated version

7 But behold, the Lord in his great mercy sent his angel to declare unto me that I must stop the work of destruction among his people; yea, and I have seen an angel face to face, and he spake with me, and his voice was as thunder, and it shook the whole earth. 

8 And it came to pass that I was three days and three nights in the most bitter pain and anguish of soul; and never, until I did cry out unto the Lord Jesus Christ for mercy, did I receive a remission of my sins. But behold, I did cry unto him and I did find peace to my soul.

I would like to propose that this really is the abbreviated version of what Alma actually told Shiblon. Since his message started out the same, I think it's reasonable to assume it also continued the same when Alma told his sons about this experience. But it had already been written in Alma 36 and there was no need to repeat everything in writing in Alma 38, so it was kept much shorter. But we see that the two quoted verses in Alma 38 pretty much sums up Alma 36:6-23. Alma 36:24-30 is a repetition of the already quoted beginning, in reverse order, to complete the chiasmus.

Not until Alma completes his message in Alma 36, do the two admonitions to his sons start to deviate. Helaman is the next record keeper so he receives specific instructions in Alma 37, whereas Shiblon receives his personal admonitions in Alma 38:9-15.