2 Nephi 8

Through the writings of Isaiah, the Lord says to Israel -

"Hearken unto me, my people; and give ear unto me, O my nation; for a law shall proceed from me, and I will make my judgment to rest for a light for the people."  (Book of Mormon | 2 Nephi 8:4)

And -

"Hearken unto me, ye that know righteousness, the people in whose heart I have written my law, fear ye not the reproach of men, neither be ye afraid of their revilings."  (Book of Mormon | 2 Nephi 8:7)

In both cases, the Lord refers to "law" or "my law".  Ordinances, laws, and covenants are closely related.  With ordinances comes His Law by which we covenant to obey which laws are written on our hearts.  In other words -

"Awake, awake, put on thy strength, O Zion; put on thy beautiful garments..."  (Book of Mormon | 2 Nephi 8:24)

Great promises follow such -

"For the Lord shall comfort Zion, he will comfort all her waste places; and he will make her wilderness like Eden, and her desert like the garden of the Lord. Joy and gladness shall be found therein, thanksgiving and the voice of melody."  (Book of Mormon | 2 Nephi 8:3)