The "Radical Departure" is the Mass BOYCOTT of the Sunday Observance of our Lord's resurrection, which is indeed a modern day invention and has no roots in Apostolic teaching, thought or practice..
Totally wrong---the radical departure if from the 7th day Sabbath to Sunday. There is nothing stated in the bible of keeping Sunday observance for any reason. And history itself proves you wrong. It was not until the Council of Laodicea in 364 that the 7thy day Sabbath was declared anathema to Christ. Before that---Christians kept the 7th day Sabbath and it was only through Catholicism that Sunday became the day to worship God.
Canon XXIX: “
Christians must not judaize by resting on the Sabbath, but must work on that day, rather honouring the Lord’s Day; and, if they can, resting then as Christians. But if any shall be found to be judaizers, let them be anathema from Christ.” (Percival Translation).
You do not even know you own church's history nor what you church says about the Sabbath.
They should, if the Scripture were their only rule, wash the feet of one another, according to the command of Christ, in the 13th chap. of St. John; —they should keep, not the Sunday, but the Saturday, according to the commandment, "Remember thou keep holy the SABBATH-day;" for this commandment has not,
in Scripture, been changed or abrogated;... Rev. Stephen Keenan,
A Doctrinal Catechism; New York in 1857, page 101 Imprimatuer
Had she not such power, she could not have done that in which all modern religionists agree with her; —she could not have substituted the observance of Sunday the first day of the week, for the observance of Saturday the seventh day, a change for which there is no Scriptural authority. Rev. Stephen Keenan,
A Doctrinal Catechism; New York in 1857, page 174
"The Church, on the other hand, after changing the day of rest from the Jewish Sabbath, or seventh day of the week, to the first, made the Third Commandment refer to Sunday as the day to be kept holy as the Lord's Day. The Council of Trent (Sess. VI, can. xix) condemns those who deny that the Ten Commandments are binding on Christians." The Catholic Encyclopedia, Commandments of God, Volume IV, © 1908 by Robert Appleton Company, Online Edition © 1999 by Kevin Knight, Nihil Obstat - Remy Lafort, Censor Imprimatur - +John M. Farley, Archbishop of New York, page 153.
''The [Roman Catholic] Church changed the observance of the Sabbath to Sunday by right of the divine, infallible authority given to her by her founder, Jesus Christ. The Protestant claiming the Bible to be the only guide of faith, has no warrant for observing Sunday. In this matter the Seventh-day Adventist is the only consistent Protestant.'' The Catholic Universe Bulletin, August 14, 1942, p. 4.
"All of us believe many things in regard to religion that we do not find in the Bible. For example, nowhere in the Bible do we find that Christ or the Apostles ordered that the Sabbath be changed from Saturday to Sunday. We have the commandment of God given to Moses to keep holy the Sabbath Day, that is the 7th day of the week, Saturday. Today most Christians keep Sunday because it has been revealed to us by the Church outside the Bible." The Catholic Virginian, "To Tell You The Truth,” Vol. 22, No. 49 (Oct. 3, 1947).
"... 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 sanctify." The Faith of Our Fathers, by James Cardinal Gibbons, Archbishop of Baltimore, 88th edition, page 89. Originally published in 1876, republished and Copyright 1980 by TAN Books and Publishers, Inc., pages 72-73.
"The Church, on the other hand, after changing the day of rest from the Jewish Sabbath, or seventh day of the week, to the first, made the Third Commandment refer to Sunday as the day to be kept holy as the Lord's Day. The Council of Trent (Sess. VI, can. xix) condemns those who deny that the Ten Commandments are binding on Christians." The Catholic Encyclopedia, Commandments of God, Volume IV, © 1908 by Robert Appleton Company, Online Edition © 1999 by Kevin Knight, Nihil Obstat - Remy Lafort, Censor Imprimatur - +John M. Farley, Archbishop of New York, page 153.
''The [Roman Catholic] Church changed the observance of the Sabbath to Sunday by right of the divine, infallible authority given to her by her founder, Jesus Christ. The Protestant claiming the Bible to be the only guide of faith, has no warrant for observing Sunday. In this matter the Seventh-day Adventist is the only consistent Protestant.'' The Catholic Universe Bulletin, August 14, 1942, p. 4.
"All of us believe many things in regard to religion that we do not find in the Bible. For example, nowhere in the Bible do we find that Christ or the Apostles ordered that the Sabbath be changed from Saturday to Sunday. We have the commandment of God given to Moses to keep holy the Sabbath Day, that is the 7th day of the week, Saturday. Today most Christians keep Sunday because it has been revealed to us by the Church outside the Bible." The Catholic Virginian, "To Tell You The Truth,” Vol. 22, No. 49 (Oct. 3, 1947).
"... 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 sanctify." The Faith of Our Fathers, by James Cardinal Gibbons, Archbishop of Baltimore, 88th edition, page 89. Originally published in 1876, republished and Copyright 1980 by TAN Books and Publishers, Inc., pages 72-73.
but
Colossians 2:15-17 explicitly says it was a shadow and is no longer binding once Christ came.
You are quite wrong--The Sabbath was never la shadow of things tgo come!! It always pointed backward to creation and to God who created everything.
Exo 20:11
For in six days the LORD made heaven and earth, the sea, and all that in them is,
and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it.