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.

When will the gifts of the Spirit he no longer needed?
By what commands has God guarded the marriage relation?
What are the three essentials to an official seal?
On opening the fifth seal, what was seen under the altar?
7. What spirits stand ever ready to deceive and ruin those who are off guard or bent on going astray?
For what purpose did God give His Son to the world?
What will flow through the city?

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