Christians do not do after the manner of the Jews who observe the Sabbath; nor eat of the unleavened bread as is the manner of the Papacy and its offshoots, but do according to the Apostolic teaching: "every Lord's day gather yourselves together, and break bread, and give thanksgiving after having confessed your transgressions, that your sacrifice may be pure." (Didache) This practice of the Apostles is recorded in Acts 20:7. The "pure sacrifice" is an allusion to Numbers 28:9 where the Lord commanded the Israelites: "And on the sabbath-day you shall offer two lambs of a year old without blemish, and two tenth deals of fine flour mingled with oil for a meat-offering, and a drink-offering." The Jews sacrificed animals on the Sabbath as propitiation for their sins, but the death of Christ was the sacrifice to God for Christians (Eph.5.2) and the Eucharist / Thanksgiving of the Bread and the Cup (meat and drink offering) is a proclamation of this sacrifice until his coming (1.Cor.11.26).
The Jews did not keep the Law as they should as the saints teach in the Holy Scriptures: "You received the law by the actions of Angels, and yet you have not kept it.” (Act.7.53) "For if you bring a blind victim for sacrifices, is it not evil? and if you bring the lame or the sick, is it not evil? ... And now, entreat the face of your God, and make supplication to him. These things have been done by your hands; shall I accept you? says the Lord Almighty." (Mal.1.8a,9) Now, since the Incarnation and the destruction of the temple of sacrifices, the Jews want to keep Sabbath even though there can be no offering for their sins per Numbers 28:9. As St. John Chrysostom says: "When there was need to observe the Law, they trampled it under foot. Now that the Law has ceased to bind, they obstinately strive to observe it. What could be more pitiable that those who provoke God not only by transgressing the Law but also by keeping it? On this account Stephen said: "You stiff-necked and uncircumcised in heart, you always resist the Holy Spirit" (Act.7.51), not only by transgressing the Law but also by wishing to observe it at the wrong time." (Adversus Judaeos)
Furthermore, the Didache instructs: "let not your fasts be with the hypocrites, for they fast on the second and fifth day of the week. Rather, fast on the fourth day and the Preparation (Friday)." So not only was the day of sacrifice moved to the Lord's Day (Sunday) in Apostolic times--the Day of Resurrection, because God "according to his great mercy, has regenerated us into a living hope, through the resurrection of Jesus Christ from the dead" (1.Pet.1.3b-c)--, but the fast days were also moved a day later, respectively, so as not to coincide with the observations of "hypocrites".
