The seventh day Sabbath is God’s gift to humanity. It was blessed and sanctified by God after He had created the heavens and the earth, and all the host of them. It was written into the Ten Commandments by His finger, was kept, and taught by Jesus Christ, and was observed by the apostolic church. A memorial of both creation and redemption, it should be faithfully celebrated by believers now as a day of rest, worship, and well-doing.
Here’s where the Sabbath was first instituted by God: “Thus the heavens and the earth were finished, and all the host of them. And on the seventh day God ended his work which he had made; and he rested on the seventh day from all his work which he had made. 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.” (Genesis 2:2)
Here God defines when a day commences and finishes, from evening to morning: “And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.” (Genesis 1:5) Thus we are to keep the Sabbath from sundown on Friday to sundown on Saturday.
Here is the fourth commandment: “Remember the sabbath day, to keep it holy. Six days shalt thou labour, and do all thy work: But the seventh day is the sabbath of the Lord thy God: in it thou shalt not do any work, thou, nor thy son, nor thy daughter, thy manservant, nor thy maidservant, nor thy cattle, nor thy stranger that is within thy gates: For in six days the Lord made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the Lord blessed the sabbath day, and hallowed it.” (Exodus 20:8-11)