Why is Sunday the Christian Day of Worship

Why Christians (and Catholics in particular) acknowledge Sunday as the Lord's Day (i.e. Sabbath)

So why is the Christian and Catholic “Sabbath” day on Sunday? The Sabbath is the term used for the day of religious observance for the faithful Jewish community (Friday evening to Saturday evening). Amongst Christians the day is Sunday. But why? Note that some Christians prefer to recognize Saturday as their Sabbath day (i.e. 7th Day Adventist Protestants).

First some historical background. Sunday (the day of the sun) is the name of the first day of the week. The word is probably derived from our ancestral Egyptian astrology. The week of 7 days was introduced into Roman culture in the 1st or 2nd century AD. The romans named each day after a feature in our solar system, features that were also associated with a member or personality of our creation entity (gods). Germanic nations appear to have adopted the week as a division of calendar time from the romans. “Dies Solis” became Sunday (“Sonntag” in german). “Dies Mercuri” (Mercury) became “Woensdag” in dutch or Wednesday in English. Sunday was the first day of the week according to the Jewish method of reckoning time, but was established as the day set apart from the others for faithful public and solemn worship of our creation entity.

The Church was created by Jesus Christ and the first apostles when Jesus expressed:

(all translations from the New American Bible Saint Joseph Edition which is the most accurate and faithful to the meaning of the greek original as possible)

“And I say also unto thee, that thou art Peter, and upon this rock I will build my church […]” (Matthew 16:18), and

“But you will receive power when the holy Spirit comes upon you and you will be my witnesses in Jerusalem, throughout Judea and Samaria, and to the ends of the earth.” (Acts 1:8).

And after the resurrection, reminding the apostles and followers of the prophecy of the messiah: “repentance, for the forgiveness of sins, would be preached in his name to all the nations, beginning from Jerusalem” (Luke 24:46-47).

The early Church community began meeting on Sundays soon after Christ rose from death to honor the Lord’s resurrection, which occurred on a Sunday. Acts 20:7 records that the Apostle Paul confirmed the first day of the week was the time for breaking bread in remembrance of Christ (“communion” for Catholics and the Church as originated by the Apostles and Christ). Acts was written in 62 to 70 AD by many estimates by Luke if he was indeed a companion of the Apostle Paul. The first day of the week is Sunday.

Paul the Apostle wrote in First Corinthians 16:2 the first day of the week (Sunday) was used for collections for the Church community (tithe). 1 Corinthians was written in 53 to 55 AD. The practice of meeting on the first day of the week for the celebration of the Eucharistic sacrifice is called “The Lord’s Day”.

The Didache (written sometime between 50 AD and 120 AD) (also known as the “Teaching of the 12 Apostles”) confirms on the Lord’s Day we come together to break bread and give thanks (Eucharistic sacrifice) after confessing our sins such that our sacrifice may be pure.

Saint Justin, who was martyred (executed) in 165 AD during the persecution under Marcus Aurelius, appears to be the first Christian writer to call the Lord’s Day “Sunday”.

During the first three centuries (0 to 300 AD) practice and tradition consecrated Sunday to being the Lord’s Day (Sabbath). At the sinod (council) of Elvira in Spain sometime between 300 to 324 AD, it was decreed that church attendance was expected on Sundays. Roman Emperor Constantine introduced the first civil law concerning Sunday as a non-work day in 321 AD.

Note that Jesus himself expressed that it is okay to work on the “Sabbath” if doing it for good purposes. Therefore being engaged in activities on a Sunday (or Saturday) is certainly acceptable if doing it to provide for others (i.e. family) or your own well-being to permit you to help others.  However it is highly recommended by many that the Sabbath day is the day for rest and to honor our Creator.

The 4th commandment presented to Moses says to labor 6 days and make the 7th day holy. Hence the concept of a single Sabbath day (i.e. Saturday or Sunday), but in the Christian faith we are free to choose to observe holy days every day or on 1 day (i.e. catholic masses are commonly offered every day of the week, i.e. “daily masses”). Romans 14:5-6 expresses freedom to choose which day or days to engage in holy activities or actions.  

Early historians (100 AD to 300 AD) such as Barnabas, Ignatius, and Justin Martyr recorded that the Lord’s Day was observed on Sunday by Christians throughout the region. In 150 AD Justin recorded that “on the day called Sunday, all who live in cities or in the country gather to one place, and the memoirs of the apostles or the writings of the prophets are read […] [etc]”.

Therefore it is clear that after the execution and resurrection of Jesus Christ in approximately 30 AD, the Christian “Sabbath” (“The Lord’s Day”) was selected to be on Sunday since almost the very beginning of the Christian Church, for the reason that Jesus resurrected on Sunday, and that there is freedom to choose for yourself when to honor, remember, and recognize the words of our creation entity (God), the words and deeds and sacrifice of Jesus Christ, your local, regional, and international Christian community, and discern the will of God our creation entity.