Well lets look at Samuele Bacchiocchi's book From Sabbath to Sunday: A Historical Investigation of the Rise of Sunday Observance in Early Christianity.
"...How did the change come about from Saturday to Sunday in early Christianity? To find an answer to this question I spent five years at the Pontifical University in Rome, investigating for my doctoral dissertation the earliest Christian documents. This short article represents a brief summary of my research.
Historically, the change from Sabbath to Sunday has been attributed to the ecclesiastical authority of the Roman Catholic church rather than to Biblical or apostolic precepts. Thomas Aquinas, for example, explicitly states that:
"the observance of the Lord's Day took the place of the observance of the Sabbath not by virtue of the [Biblical] precept but by the institution of the church." (1)
Recently, however, some scholars have argued that Sunday observance has a Biblical and apostolic origin. According to these scholars, from the inceptions of the Church the Apostles themselves chose the first day of the week in place of the seventh day in order to commemorate the resurrection of Christ. (2)
My own assessment of the sources is that this thesis is wrong on two counts. First, the change from Saturday to Sunday occurred sometime after 135 A.D. as a result of an interplay of political, social, pagan and religious factors to be mentioned below. Second, the change originated in Rome and not in Jerusalem. Before submitting the reasons for my conclusions, we shall briefly examine the alleged role of Christ, of the resurrection and of the Jerusalem church in the origin of Sunday.
Jesus and the Origin of Sunday
A popular view holds that Christ by his provocative method of Sabbath keeping-which caused considerable controversy with the religious leaders of His day-intended to pave the way for the abandonment of the Sabbath and the adoption of Sunday keeping instead. This view clearly distorts the intent of Christ's controversial Sabbath activities and teachings which were clearly designed not to nullify but to clarify the divine intent of the Fourth Commandment.
Christ never conceded to have broken the Sabbath commandment. On the contrary He defended Himself and His disciples from the charge of Sabbath breaking by appealing to the Scriptures: "Have you read . . ." (Matt 12:3-5). The intent of Christ's provocative Sabbath teachings and activities was not to pave the way for Sunday keeping, but rather to show the true meaning and function of the Sabbath, namely, a day "to do good" (Matt 12:8), "to save life" (Mark 3:4), to loose people from physical and spiritual bonds (Luke 13:16), and to show "mercy" rather than religiosity (Matt 12:7).
The Resurrection and the Origin of Sunday
Did the apostles introduce Sunday keeping instead of Sabbath keeping in order to commemorate Christ's resurrection by means of the Lord's Supper celebration? This view, though popular, is devoid of Biblical and historical support. The major reasons, briefly stated are the following.
No Command of Christ or of the Apostles
The New Testament never suggests or commands to celebrate Christ's resurrection by a weekly or annual Sunday celebration. This silence is noteworthy in view of the specific instructions given by Christ regarding such practices as baptism (Matt 28:19-20), the Lord's Supper (Mark 14:24-25; 1 Cor 11:23-26) and foot-washing (John 13:14-15).
If Jesus wanted the day of his resurrection to be observed as a day of rest and worship, would He not told the women and the disciples when He rose: "Come apart and celebrate My Resurrection?" Instead He told the women "Go and tell my brethren to go to Galilee" (Matt 28:10) and to the disciples "Go . . . make disciples . . . baptizing them" (Matt 28:19).None of the utterances of the risen Savior reveal an intent to memorialize His resurrection by making Sunday the new day of rest and worship.
No Designation of Sunday as Day of the Resurrection
Sunday is never called in the New Testament as "Day of the Resurrection." It is consistently called "First day of the week." The references to Sunday as day of the resurrection first appear in the early part of the fourth century. (3) By that time Sunday had become associated with the resurrection....."
"....The Earliest Reference to Sunday
The earliest explicit references to Sunday keeping are found in the writings of Barnabas (about 135 A.D.) and Justin Martyr (about 150 A.D.). Both writers do mention the resurrection as a basis for Sunday observance but only as the second of two reasons, important but not predominant. Barnabas' first theological motivation for Sunday keeping is eschatological, namely, that Sunday as "the eight day" represents "the beginning of another world." (4) Justin's first reason for the Christians' Sunday assembly is the inauguration of creation: "because it is the first day on which God, transforming the darkness and prime matter, created the world." (5)
The above indications suffice to discredit the claim that Christ's resurrection on the first day of the week caused the abandonment of the Sabbath and the adoption of Sunday. The truth is that initially the resurrection was celebrated existentially rather than liturgically, that is, by a victorious way of life rather than by a special day of worship....."
".....The attachment of the Jerusalem Church to the Mosaic Law is reflected in some of the decisions of the first Jerusalem Council held about 49-50 A.D. (See Acts 15). The exemption from circumcision is there granted only "to brethren who are of the Gentiles" (Acts 15:23). No concession is made for Jewish-Christians, who must continue to circumcise their children. Moreover, of the four provisions made applicable by the Jerusalem Council to Gentiles, one is moral (abstention from "unchastity") but three are ceremonial (even Gentile Christians are ordered to abstain "from contact with idols and from [eating] what has been strangled and from [eating] blood" (Acts 15:20). This concern of the Jerusalem Council for ritual defilement and Jewish food laws reflects its continued attachment to Jewish ceremonial law and its commands. It would be unthinkable that this Church at this early time would change the Sabbath to Sunday.
James' statement at the Jerusalem Council in support of his proposal to exempt Gentiles from circumcision but not from Mosaic laws in general, is also significant: "For generations past Moses has had spokesmen in every city; he is read every Sabbath in the synagogues" (Acts 15:21). All interpreters recognize that both in his proposal and in its justification, James reaffirms the binding nature of the Mosaic Law which was customarily taught every Sabbath in the synagogue.
Paul's Last Visit
Further insight is provided by Paul's last visit to Jerusalem. The Apostle was informed by James and the elders that thousand of converted Jews were "all zealous for the Law" (Acts 21:20). The same leaders then pressured Paul to prove to the people that he also "lived in observance of the law" (Acts 21-24), by undergoing a rite of purification at the Temple. In the light of this deep commitment to the observance of the Law, it is hardly conceivable that the Jerusalem Church would have abrogated one of its chief precepts-Sabbath keeping-and pioneered Sunday worship instead.
Did Sunday Originate After 70 A.D.?
The foregoing evidences has led some scholars to argue for the Palestinian origin of Sunday observance at a slightly later time, namely, after the Roman destruction of the Temple in 70 A.D. (8) They presume that the flight of the Christians from Jerusalem to Pella as well as the psychological impact of the destruction of the Temple weaned Palestinian Christians away from Jewish observances such as Sabbath keeping.
This assumption is discredited by both Eusebius and Epiphanius who inform us that the Jerusalem Church after 70 A.D. and until Hadrian's siege of Jerusalem in 135 A.D., was composed of and administered by converted Jews, characterized as "zealous to insist on the literal observance of the Law." (9) The orthodox Palestinian Jewish-Christian sect of the Nazarenes, who most scholars regard as "the very direct descendants of the primitive community" (10) of Jerusalem, retained Sabbath keeping on Saturday until the fourth century. Indeed, seventh-day Sabbath keeping was regarded as one of this Church's distinguishing characteristics. (11) This implies that Sabbath observance was not only the traditional custom of the Jerusalem Church, but also of Palestinian Jewish-Christians long after 70 A.D.
Of all the Christian Churches, the Jerusalem Church was both ethnically and theologically the closest and most loyal to Jewish religious traditions, and thus the least likely to change the day of the Sabbath....."