But the seventh day is the sabbath of the LORD thy God:
Exodus 20:10
in many scriptures, and at many different times.
He never so claimed the first day,
but gave it to man for labor.
He blessed and sanctified
the seventh day.
He neither blessed
nor sanctified the first day.
He commanded that the seventh day
be kept holy.
He never commanded
to keep the first day.
There is but one commandment in the Bible for a weekly Sabbath, and that says the seventh day." Joseph Waggoner