@newton, the essence of the Sabbath is not the exact day, it is the idea itself of spending a day off for the Lord alone, weather it be Sunday or Saturday, as long as you assigned that day to worship Him. That is what Jesus also meant when He explicitly disobeyed the strict observance of Sabbath by the pharisees by healing the sick and His apostles doing labors prohibited during Sabbath.
Please stop policing our faith, you and your predecessors have had so much futile attempts for the past 2000 years, look at where we are now, strong as ever the church Jesus himself instituted.