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. (2 Ne. 4:5.)
Apparently knowing he would soon die, Lehi followed biblical tradition by gathering his children and their children in order to counsel and bless them.
Blessings by fathers as they neared death was a common practice in Old Testament times. For example, one of Lehi's ancestors, Jacob, blessed his children and their children before he died. (Genesis chapters 48-49.)
With the blessing, a dying man usually transmitted his status and estate to his heir or heirs, and gave admonitions for righteous living and the promise of subsequent favor from the Lord.
The Old Testament also has other examples of how blessings or auspicious words were given at various times, such as upon departure for a journey (Gen. 24:60) and at marriage (Ruth 3:10-12). Numerous references are made about blessings being pronounced at births, and upon greeting friends.
In his October 1986 general conference address, Elder Gardner H. Russell of the First Quorum of the Seventy spoke of fathers giving blessings to their children:
"Fathers everywhere, consider the gift of love you can give your children when you are worthy and you lay your hands upon their heads to pronounce inspired father's blessings as the family patriarch. They will feel a continuing outpouring of your love, which will keep them close to you and to the Lord."
Undoubtedly, Lehi wished his posterity to feel his love and remember the Lord and His ways.