The Jews worship on the Sabbath (Saturday)

The Jews observe the 4th Commandment of Exodus 20:8-11, "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 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 hollowed it."

Sunday worship has its origin in the Roman Catholic Church. It was inherited and retained by the Protestant churches after the Reformation. See "Day of Worship--Roman Catholic" for details.