Remember the Sabbath day to keep it holy. Six days shalt thou labor 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, they man-servant, not they maid-servant, not 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 xx.3-11
it was dedicated to the Sun, by the heathen nations.
The word Sunday, never occurs in the Bible, and in no instance is the word Sabbath applied to the first day of the week, but always refers to the seventh day." T.M. Preble