reply to post by JesuitGarlic
Christ fulfilled the Law (the Old Covenant was promised fulfillment in the Messiah, which is Christ); Christ did not abolish the Law, but fulfilled
it. The New Covenant observes that which was promised in the Old, and this nuance is tricky, as it can lead to the erroneous misunderstanding of
Supersessionism which posits God as a trickster and liar in effect. In fact, the New was always alluded to in the Old via typology. Jeremiah 31:
 Behold the days shall come, saith the Lord, and I will make a new covenant with the house of Israel, and with the house of Juda:  Not
according to the covenant which I made with their fathers, in the day that I took them by the hand to bring them out of the land of Egypt: the
covenant which they made void, and I had dominion over them, saith the Lord.
"If, therefore, those who were brought up in the ancient order of things have come to the possession of a new hope, no longer observing the Sabbath,
but living in the observance of the Lord's Day, on which also our life has sprung up again by Him and by His death--whom some deny, by which mystery
we have obtained faith, and therefore endure, that we may be found the disciples of Jesus Christ, our only Master." Ignatius, To the Magnesians, 9:1
Isaiah 1:13 - God begins to reveal His displeasure with the Sabbath.
Matt. 28:1; Mark 16:2,9; John 20:1,19- the Gospel writers purposely reveal Jesus' resurrection and appearances were on Sunday. This is because Sunday
had now become the most important day in the life of the Church.
Acts 20:7 - this text shows the apostolic tradition of gathering together to celebrate the Eucharist on Sunday, the "first day of the week." Luke
documents the principle worship was on Sunday because this was one of the departures from the Jewish form of worship.
1 Cor. 16:2 - Paul instructs the Corinthians to make contributions to the churches "on the first day of the week," which is Sunday. This is because
the primary day of Christian worship is Sunday.
Col. 2:16-17 - Paul teaches that the Sabbath was only a shadow of what was fulfilled in Christ, and says "let no one pass judgment any more over a
2 Thess. 2:15 - we are to hold fast to apostolic tradition, whether it is oral or written. The 2,000 year-old tradition of the Church is that the
apostles changed the Sabbath day of worship from Saturday to Sunday.
Heb. 4:8-9 - regarding the day of rest, if Joshua had given rest, God would not later speak of "another day," which is Sunday, the new Sabbath.
Sunday is the first day of the week and the first day of the new creation brought about by our Lord's resurrection, which was on Sunday.
Heb. 7:12 - when there is a change in the priesthood, there is a change in the law as well. Because we have a new Priest and a new sacrifice, we also
have a new day of worship, which is Sunday.
Rev 1:10 - John specifically points out that he witnesses the heavenly Eucharistic liturgy on Sunday, the Lord's day, the new day of rest in
Matt. 16:19; 18:18 - whatever the Church binds on earth is bound in heaven. Since the resurrection, Mass has been principally celebrated on Sunday.