4 Nephi 1:12

And they did not walk any more after the performances and ordinances of the law of Moses, but they did walk after the commandments which they had received from their Lord and their God, continuing in fasting and prayer, and in meeting together oft, both to pray and to hear the word of the Lord.

They stopped following the law of Moses. Instead, they followed the teachings they had received from their Lord and God. They kept fasting and praying. They met together often to pray and hear God’s word.

They no longer followed the old law of Moses with its rituals and ceremonies. Instead, they lived by the teachings they’d received from their Lord and God—fasting, praying, gathering regularly to worship and hear God’s word.