By what authority was Sunday Sabbath-keeping instituted?

Answer

By the authority of the Catholic Church. See page 131.

22. After being united with Christ in the likeness of His death and resurrection, what should the believer do?
How did Christ teach the people?
What question did the performing of these miracles lead many to ask?
In what miracle did Christ bring to a climax His works on earth?
What provision has been made so that we may keep God's law?
What is said of the character of these scaled ones?
What is the last enemy to be destroyed?

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