Why Sunday, and Not Saturday?
“Now about the collection for God’s people: Do what I told the Galatian churches to do. On the first day of every week, each one of you should set aside a sum of money in keeping with his income, saving it up, so that when I come no collections will have to be made” (1 Cor 16:1,2).
“On the first day of the week we came together to break bread. Paul spoke to the people and, because he intended to leave the next day, kept on talking until midnight” (Acts 20:7).
Since so many in the early ecclesias were Jews, and since they were already in the habit of observing the Sabbath, why were their regular meetings at this time held on Sundays rather than Saturdays?
The obvious answer is that “the first day of the week” was plainly associated with the resurrection of the Lord Jesus Christ (Matt 28:1; Mark 16:2,9; Luke 24:1; John 20:1,19), and that the breaking of bread was a commemoration not just of his death but especially of his resurrection.
At the very beginning, and perhaps for a couple of generations, the Jewish Sabbath, that is Saturday, was set aside and observed by many Jewish Christians. They may have frequented the synagogues (Paul and his companions did this regularly) for the purpose of meeting with friends and relatives, and probably also for the purpose of preaching the gospel to their fellow-Jews.
Of course, when they attended a synagogue, they could scarcely have a breaking of bread service there which was exclusive to believers. Nor could Gentile believers be expected to attend the synagogue at all. So they would have to meet later, probably after synagogue services (morning and evening?) were finished.
Therefore, if Jewish Christians wanted to attend synagogue services, this would leave Saturday night available, after the Sabbath had officially ended, for memorial meeting. This may account for Paul, in one instance, speaking until midnight (Acts 20:7). It is not likely that Paul began speaking in the morning or even at midday, and continued thereafter until midnight, but rather that he began at 8 pm or 9 pm, and the service continued until midnight.
Regular evening services, as soon as the Jewish Sabbath ended, might help explain why Paul calls the breaking of bread “the Lord’s Supper” (1 Cor 11:20). The word he uses for “supper” is the Greek “deipnon”, which means exactly that: an evening meal, and quite often a banquet. This also supports the idea that the earliest believers celebrated the breaking of bread on Saturday evening (right after the Jewish Sabbath ended), and not Sunday morning.
Because it was an evening service, and because it was for partaking the bread and the wine, such a “supper” would evoke both the Jewish Passover and traditional Jewish Sabbath services, as well as Christ’s own evening “Passover” which he kept with his disciples before he suffered.
Jews would keep the Sabbath by refraining from work. This was presumably allowed in most places in the Roman Empire because their religion was usually recognized by the authorities. But by Sunday morning they may have had to follow local custom and be available for work, market, and other business activities. Nevertheless, this would leave Saturday night, after synagogue services were finished, for Christians to meet together.
Keep in mind, also, that by Jewish reckoning, the “first day”, or Sunday, began when the sun went down in the evening after the 24-hour Sabbath finished.
Later, when Christianity became a recognized religion in parts of the Roman Empire and elsewhere, Sunday would likely be recognized as a day of rest also. By then, Christians might have begun to hold meetings at various times on Sunday (as we now define it, from midnight to midnight). But in the beginning, and for several generations, Saturday evening (as Gentiles saw it), but very early on Sunday (as Jews saw it), may have been the most convenient time for the Lord’s Supper.
The Origin of the Organic World – Part One