“If Protestants would follow the Bible, they would worship God on the Sabbath Day. In keeping the Sunday they are following a law of the Catholic Church.” Albert Smith, Chancellor of the Archdiocese of Baltimore, replying for the Cardinal, in a letter dated February 10, 1920.
“The observance of Sunday by the Protestants is homage they pay, in spite of themselves, to the authority of the [Catholic] Church.” Monsignor Louis Segur, ‘Plain Talk about the Protestantism of Today’, p. 213. What Important Question Does the Papacy Ask Protestants? Protestants have repeatedly asked the papacy, "How could you dare to change God's law?" But the question posed to Protestants by the Catholic church is even more penetrating. Here it is officially: ""You will tell me that Saturday was the Jewish Sabbath, but that the Christian Sabbath has been changed to Sunday. Changed! but by whom? Who has authority to change an express commandment of Almighty God? When God has spoken and said, Thou shalt keep holy the seventh day, who shall dare to say, Nay, thou mayest work and do all manner of worldly business on the seventh day; but thou shalt keep holy the first day in its stead? This is a most important question, which I know not how you can answer. You are a Protestant, and you profess to go by the Bible and the Bible only; and yet in so important a matter as the observance of one day in seven as a holy day, you go against the plain letter of the Bible, and put another day in the place of that day which the Bible has commanded.
The command to keep holy the seventh day is one of the ten commandments; you believe that the other nine are still binding; who gave you authority to tamper with the fourth? If you are consistent with your own principles, if you really follow the Bible and the Bible only, you ought to be able to produce some portion of the New Testament in which this fourth commandment is expressly altered."" *Library of Christian Doctrine: Why Don't You Keep Holy the Sabbath-Day? (London: Burns and Oates, Ltd.), pp. 3, 4.
"Some theologians have held that God likewise directly determined the Sunday as the day of worship in the NEW LAW, that he himself has explicitly substituted sunday for the Sabbath. But this theory is entirely abandoned. It is now commonly held that God simply gave His church the power to set aside whatever day or days she would deem suitable as holy days. The church chose sunday, the first day of the week, and in the course of time added other days as holy days." - Vincent J. Kelly, Forbidden Sunday and Feast-Day Occupations, Washington, DC, Catholic University of America Press, Studies in Sacred Theology, No. 70.,1943, p. 2. "If we consulted the Bible only, we should still have to keep holy the Sabbath Day, that is, Saturday, with the Jews, instead of Sunday; ..." -- A Course in Religion for Catholic High Schools and Academies, by Rev. John Laux M.A., Benzinger Brothers, 1936 edition, Part 1. "Sunday is a Catholic institution, and... can be defended only on Catholic principles.... From beginning to end of Scripture there is not a single passage that warrants the transfer of weekly public worship from the last day of the week to the first." Catholic Press, Aug. 25, 1900
"The Sabbath was Saturday, not Sunday. The Church altered the observance of the Sabbath to the observance of Sunday. Protestants must be rather puzzled by the keeping of Sunday when God distinctly said, 'Keep holy the Sabbath Day.' The word Sunday does not come anywhere in the Bible, so, without knowing it they are obeying the authority of the Catholic Church." Canon Cafferata, The Catechism Explained, p. 89. ''Reason and sense demand the acceptance of one or the other of these alternatives: either Protestantism and the keeping holy of Saturday, or Catholicity and the keeping holy of Sunday. Compromise is impossible.'' John Cardinal Gibbons, The Catholic Mirror, December 23, 1893.