It was Preston who convinced a small bunch of Millerites that Saturday, not Sunday, was the biblical Sabbath. It was only after the Great Disappointment of 1844 that the Millerite brethren had time to consider the proper day of worship and rest - prior to October 22nd of that year, a preoccupation with the second advent of Jesus, presumed to be foretold in Scripture as occurring on October 22, 1844.
After the Lord did not return as expected, the Millerites, suddenly with extra time on their hands, turned their attention to the nuts and bolts of organization and worship. Rachel Oakes Preston's emphasis on Saturday as Sabbath eventually became a key tenet of Millerite-turned-Seventh-day Adventist belief.
