Lehi's blessing to the children of Laman

Lehi's blessing to the sons and daughters of Laman is short enough to quote here in full

3 Wherefore, after my father had made an end of speaking concerning the prophecies of Joseph, he called the children of Laman, his sons, and his daughters, and said unto them: Behold, my sons, and my daughters, who are the sons and the daughters of my firstborn, I would that ye should give ear unto my words.

4 For the Lord God hath said that: Inasmuch as ye shall keep my commandments ye shall prosper in the land; and inasmuch as ye will not keep my commandments ye shall be cut off from my presence.

5 But behold, my sons and my daughters, I cannot go down to my grave save I should leave a blessing upon you; for behold, I know that if ye are brought up in the way ye should go ye will not depart from it.

6 Wherefore, if ye are cursed, behold, I leave my blessing upon you, that the cursing may be taken from you and be answered upon the heads of your parents.

7 Wherefore, because of my blessing the Lord God will not suffer that ye shall perish; wherefore, he will be merciful unto you and unto your seed forever.

The blessing is given to Laman's children, but they seem to represent 'children/sons/daughters' in a wider sense, meaning posterity. Later in the Book of Mormon, we see how various elements of this blessing are fulfilled or referenced when it talks about the Lamanites.

2 Nephi 5:21

Wherefore, the word of the Lord was fulfilled which he spake unto me, saying that: Inasmuch as they will not hearken unto thy words they shall be cut off from the presence of the Lord. And behold, they were cut off from his presence.

 Alma 23:6

I say unto you, as the Lord liveth, as many of the Lamanites as believed in their preaching, and were converted unto the Lord, never did fall away.

Jacob 3:7

their unbelief and their hatred towards you is because of the iniquity of their fathers 

Alma 9:16

For there are many promises which are extended to the Lamanites; for it is because of the traditions of their fathers that caused them to remain in their state of ignorance; therefore the Lord will be merciful unto them

Jacob 3:6

the Lord God will not destroy them, but will be merciful unto them; and one day they shall become a blessed people.

Observe how Helaman 15:10-16 in particular contains the key elements from Lehi's blessing to Laman's children when it discusses the state and the fate of the Lamanites.

10 And now, because of their steadfastness when they do believe in that thing which they do believe, for because of their firmness when they are once enlightened, behold, the Lord shall bless them and prolong their days, notwithstanding their iniquity—

11 Yea, even if they should dwindle in unbelief the Lord shall prolong their days, until the time shall come which hath been spoken of by our fathers, and also by the prophet Zenos, and many other prophets, concerning the restoration of our brethren, the Lamanites, again to the knowledge of the truth—

12 Yea, I say unto you, that in the latter times the promises of the Lord have been extended to our brethren, the Lamanites; and notwithstanding the many afflictions which they shall have, and notwithstanding they shall be driven to and fro upon the face of the earth, and be hunted, and shall be smitten and scattered abroad, having no place for refuge, the Lord shall be merciful unto them.

13 And this is according to the prophecy, that they shall again be brought to the true knowledge, which is the knowledge of their Redeemer, and their great and true shepherd, and be numbered among his sheep.

14 Therefore I say unto you, it shall be better for them than for you except ye repent.

15 For behold, had the mighty works been shown unto them which have been shown unto you, yea, unto them who have dwindled in unbelief because of the traditions of their fathers, ye can see of yourselves that they never would again have dwindled in unbelief.

16 Therefore, saith the Lord: I will not utterly destroy them, but I will cause that in the day of my wisdom they shall return again unto me, saith the Lord.

Side note: 2 Nephi 4:5 is also a quote from Proverbs 22:6

Train up a child in the way he should go: and when he is old, he will not depart from it.