“The Law of Moses and the Sabbath”

Joseph F. McConkie, Robert L. Millet
Some have falsely supposed that Sabbath observance commenced with the law of Moses. This is not the case. The commandment given on Sinai was to “remember the sabbath day,” its inclusion among the Ten Commandments being but a reminder that from the beginning the seventh day had been held sacred (Genesis 2:2-3). The renewal of this commandment by revelation to the Prophet Joseph Smith clearly establishes that our obligation to keep the Sabbath holy is a part of the fulness of the gospel (D&C 59:9-14). See also commentary on 2 Nephi 25:24.

Doctrinal Commentary on the Book of Mormon, Vol. 2