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.

What were these gifts that Christ gave to men?
How was the prophecy given?
What definite period is mentioned under this trumpet?
To what place were the angels that sinned cast?
What is said of charity in the Scriptures?
Whatever may come, what blessed assurance has everyone who loves God?
Whose names are in the foundations of the holy city?

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