By what authority was Sunday Sabbath-keeping instituted?

Answer

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

What great gift comes with our acceptance of Christ?
How intimate is His union with believers?
10. After the fall, what sort of marriages were introduced by men, which were productive of great evil?
How does Paul describe this dedication of the covenant?
What, according to the prophecy of Daniel, was to characterize the time of the end?
For what purpose will Christ come again?
What has Christ promised the overcomer?

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