Sabbath Observance

"By modern revelation the Lord has commanded that on the Sabbath we 'rest from [our] labors' and 'pay [our] devotions unto the Most High' and that on this day we 'do none other thing' (D&C 59:10, 13). When we keep this commandment of our Creator, we qualify for His promised blessings. He who created us knows what patterns of behavior will allow us to achieve our maximum physical and spiritual performance, and He has given us commandments designed to guide us into that behavior. When we honor the Sabbath day, we separate ourselves from most of the world, but we are blessed richly for it."

Church Leaders
Dallin H. Oaks
General Authorities
"Push Back Against the World," BYU-Hawaii commencement, Feb 25, 2017.

And I, God, blessed the seventh day, and sanctified it; because that in it I had rested from all my work which I, God, had created and made.

Pearl of Great Price
Moses 3:3

"Old Testament scriptures taught that the earth is the Lord’s (Psalms 24:1), that the land was to rest every seven years (Leviticus 25), and that all humankind and animals were to rest on the Sabbath. New Testament teachings emphasized the Lord as a good shepherd who watched over his flocks (John 10) and a worker who tended the vineyards (John 15)."

Other Sources
Gary C. Bryner
Other Writings of Mormons
"Theology and Ecology: Religious Belief and Environmental Stewardship," in BYU Studies 49, no. 3 (2010)

And God blessed the seventh day, and sanctified it: because that in it he had rested from all his work which God created and made.

Old Testament
Genesis 2:3

And on the seventh day I, God, ended my work, and all things which I had made; and I rested on the seventh day from all my work, and all things which I had made were finished, and I, God, saw that they were good;

Pearl of Great Price
Moses 3:2