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 should we say for such a Saviour?
What does the imputed righteousness of Christ enable God to do, and still be just?
In what condition are all men?
What are all admonished to do when these signs have appeared?
What does He say He will bring with Him when He comes?
What has God promised His children when passing through trials and afflictions?
What are we admonished to overcome?

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