“The early Christians for several hundred years continued to call the Jewish day ‘the Sabbath,’ generally repudiating it as abolished, and always claiming Sunday as the day of Christian worship-the Lord’s day. (See Revelation 1:10 and any Church history.) After the Jewish day had long been dropped out of notice, the word ‘Sabbath’ came to be used for the Christian rest day. It would have been better if the inspired term ‘Lord’s day’ had been always retained and exclusively used. RCASDA 59.1
“How much, then, does it prove in favor of the Jewish Sabbath to find that it was still called ‘the Sabbath,’ or that it was kept by the Jewish Christians, or even by Paul himself? -Just nothing at all.”—Mich. Christian Advocate of Sept. 17 and 24, 1887. RCASDA 59.2