“It was the Catholic church which… transferred the rest to  the Sunday… Thus the observance of Sunday by the Protestants is an homage they pay, in spite of themselves, to the authority of the [Catholic] Church.”

Monsignor Louis Segur –  Plain Truth About Protestantism, p.213

"You may read the Bible from Genesis to Revelation, and you will not find a single line authorizing the sanctification of Sunday. The Scriptures enforce the religious observance of Saturday, a day which we never sanctified."  

James Cardinal Gibbons, The Faith of Our Fathers (1917 ed.), pp.72,73