By what authority was Sunday Sabbath-keeping instituted?

Answer

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

Upon what basis has Christ taught us to ask forgiveness?
To whom are sinners brought by conversion?
18. In what statement was Christ promised as a Savior and Deliverer of the race as soon as sin entered?
7. What questions asked by its worshippers indicate the great station to which this beast-power was to attain?
For what purpose was the Revelation given?
With what should our prayers be mingled?
Who notes the groans of the prisoner?

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