In truth, every day is a good and proper day to worship our God. Nevertheless, Sunday gradually replaced Saturday as the major day of worship for most Christians:
Following the death and resurrection of Jesus, the early Christians began meeting on Sundays almost immediately. Jesus was resurrected early Sunday morning (Mark 16:9), and one week later on Sunday evening, the disciples were gathered together and Jesus appeared to them (John 20:19). They were gathered also on the next Sunday, when Jesus appeared to them again–this time Thomas was present. On one of those occasions, Jesus told his disciples to stay in Jerusalem until they received the Holy Spirit which would empower them to fulfill their mission to Jerusalem, Judea, Samaria, and to the uttermost parts of the Earth (Acts 1:3-8). Seven weeks after the resurrection, the Christian community was all gathered together on the ‘Day of Pentecost’, and the Holy Spirit came in dramatic fashion–over 3,000 were converted that day. It was also a Sunday–Pentecost is always on a Sunday (see: Lev. 23:15-16)–many historians refer to that day as the ‘birthday of the Church’. As you can see, early-on, Sunday became a regular meeting day for the Apostles and the first century Church. Soon, they began referring to Sunday as ‘The Lord’s Day’ in commemoration of the Resurrection (Rev. 1:10). The Resurrection, ‘the appearances’, Pentecost–all on Sunday–help to elevate the importance of the first day of the week among early Christians–none of these events could be called ‘man made’.
Sunday, however, didn’t completely replace the Sabbath for these early Jewish Christians. They continued to go to their local Synagogues and honor Jewish laws and customs on Saturday (Fri. sunset to Sat. sunset),–but ‘broke bread’ together (Communion) and had Christian meetings on Sunday. Many early Jewish Christians continued to honor the Sabbath this way, clear into the later part of the 4th century. Bishop John Chrysostom, in a series of sermons preached in 386-387 AD, railed against Jewish Christians who continued to worship in Synagogues on Saturdays and then attend Mass at Church on Sundays. He demanded that they make up their minds, and forbade any from attending Jewish services or celebrations. In many cities, Jewish Christians were kicked out of the local Synagogues, particularly after 70 AD. The Christian meetings, then increasingly became their only worship service. By the end of the 4th century, the separation between Judaism and Christianity was substantially complete. As the Church expanded among ‘gentiles’, there arose a major controversy within the Christian community. Many demanded that the ‘goyim’ become Jews, and follow the Mosaic Law. Others like the Apostle Paul, and Peter, believed that this was an unnecessary burden. An Apostolic Council was called to resolve the issue. After much discussion, they came to an agreement which they believed was inspired by the Holy Spirit (See: Acts 15). They did not require gentile Christians to adhere to the Mosaic Law, but offered the following:
It seemed good to the Holy Spirit and to us not to burden you with anything beyond the following requirements:
You are to abstain from food sacrificed to idols, From blood, From the meat of strangled animals, And from sexual immorality.
You will do well to avoid these things. (Acts 15:28-29)
Notice, that the Mosaic Sabbaterian laws were not mentioned or applied to the Gentiles.
As the Church became increasingly ‘gentile’, The ‘Lord’s Day’ became the dominant day for Christian meetings and worship (see: Acts 20:7, I Cor. 16:2). While Saturday was a ‘day off’ in Jewish communities, Sunday was a primary day for religious observance among the Greeks and Romans. Even servants and slaves could get some time off to worship on Sundays. Did Sunday become the primary worship day merely because of cultural accommodation? Apostle Paul didn’t think so! He taught that every day was a good day to worship the Lord. When ‘Judaizers’ came to the Church in Galatia, they taught the Galatians to observe the Sabbaths and special days of the Jewish year. Paul used language that pointed to Numbers 28-29 and showed displeasure for their unnecessary observance. Later in Rome, some Jewish Christians were judging their ‘Gentile’ Christian brothers for not eating properly, and for not observing the Sabbaths (Rom. 14:1-12), Paul corrects this faulty judgment. Even today, this scripture speaks to us about being careful not to judge one another concerning the days we choose to worship on, or the food we eat , and the drink we consume. I am happy to let Seventh Day Baptists & Adventists, Messianic Jews, and others, worship on Saturday (or Fri. Evenings) and bless them in their convictions. However, I do hope that they will not judge me if I am happy to worship on ‘The Lord’s Day’, or any other day for that matter. This is not a matter that Christians should divide over. In truth, every day is a good day to worship our God.
Also note: There are ample references from the early Christian writings of the Apostolic Fathers (disciples of the Apostles) that ‘The Lord’s Day’–Sunday, became the dominant day for Christian worship by the end of the first century and early second–long before the Roman church began to dominate in the 4th century.