Which day did God include in the Ten Commandments?

“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.” — Exodus 20:8–11 (KJV)

“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 2:1–3 (KJV)

According to our calendar, which is the seventh day: Sunday or Saturday?

“And when the sabbath was past, Mary Magdalene, and Mary the mother of James, and Salome, had bought sweet spices, that they might come and anoint him.”

“Now when Jesus was risen early the first day of the week, he appeared first to Mary Magdalene, out of whom he had cast seven devils.” — Mark 16:1–2, 9 (KJV)

NOTE: We all know that Jesus Christ, the Son of God, rose from the dead on Sunday. Therefore, Sunday is the first day of the week, and Saturday is the seventh day, just as the Holy Scriptures affirm.

Did the prophets obey the Lord's commandment by observing and teaching the Sabbath?

“If thou turn away thy foot from the sabbath, from doing thy pleasure on my holy day; and call the sabbath a delight, the holy of the LORD, honourable; and shalt honour him, not doing thine own ways, nor finding thine own pleasure, nor speaking thine own words.” — Isaiah 58:13 (KJV)

“Moreover also I gave them my sabbaths, to be a sign between me and them, that they might know that I am the LORD that sanctify them.”

“I am the LORD your God; walk in my statutes, and keep my judgments, and do them; And hallow my sabbaths; and they shall be a sign between me and you, that ye may know that I am the LORD your God.” — Ezekiel 20:12–20 (KJV)

“Keep the sabbath day to sanctify it, as the LORD thy God hath commanded thee.” — Deuteronomy 5:12 (KJV)

Did Christ and the apostles obey this commandment?

“Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil. For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.” — Matthew 5:17–18 (KJV)

“And he said unto them, The sabbath was made for man, and not man for the sabbath: Therefore the Son of man is Lord also of the sabbath.” — Mark 2:27–28 (KJV)

“And that day was the preparation, and the sabbath drew on. And the women also, which came with him from Galilee, followed after, and beheld the sepulchre, and how his body was laid. And they returned, and prepared spices and ointments; and rested the sabbath day according to the commandment.” — Luke 23:54–56 (KJV)

Much more could be written about the Sabbath, for the Bible speaks of it from beginning to end.

Unfortunately, the religious world does not recognize this day of rest as a commandment from God. Instead, the opposite is practiced, directly disobeying the commandment that God Himself wrote with His own finger (Exodus 31:18).

This demonstrates how sacred and important obedience to this commandment is, for it accomplishes nothing to obey one part of God's law while disobeying another (James 2:10).

“And he gave unto Moses, when he had made an end of communing with him upon mount Sinai, two tables of testimony, tables of stone, written with the finger of God.” — Exodus 31:18 (KJV)

“For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all.” — James 2:10 (KJV)