Do Protestant writers acknowledge the same?

Answer

They do.
NOTE - "IS there no express commandment for observing the first day of the week as Sabbath,
instead of the seventh day?-None whatever. Neither Christ, nor His apostles, nor the first Christians
celebrated the first day of the week instead of the seventh as the Sabbath."-New York Weekly Tribune,
May 24, 1900.
"The Scriptures nowhere call the first day of the week the Sabbath. . . . There is no Scriptural
authority for so doing, nor of course any Scriptural obligation." The Watchman (Baptist).
"The observance of the first instead of the seventh day rests on the testimony of the church, and
the church alone.' -- Hobart Church News, July 2, 1894.
For additional testimonies, see reading on page 146.

Just before the fall of Babylon, what did her king do?
8. By what command did the king repudiate the religion taught in Babylon by Daniel and others who feared God?
What is the love of God declared to be?
Why was double manna given on the sixth day?
Before he was afflicted, what did he do?
Who notes the groans of the prisoner?
What will he reap who sows to the Spirit?

Questions & Answers are from the book Bible Readings for the Home Circle