Many Catholics are at a loss for words when explaining why we worship on Sunday rather than Saturday because they just take it for granted that that�s when Christians worship. However, not all Christians worship on Sunday; Seventh-Day Adventists still observe Saturday as their day of worship and criticize those that don�t. How would one respond to them? On what basis did the Catholic Church apparently do away with one of the 10 Commandments?
God commanded the Jews to worship on Saturday to commemorate creation (Genesis 2:2-3, Exodus 20:8-11, 31:12-17), and because Jesus came to fulfill the Old Covenant Laws (Matthew 5:17-18), we should take this as the starting point for our investigation into why Christians worship on Sunday. God created everything good (Genesis 1:31), including man, who was made in His image (Genesis 1:26-27), so of course creation is worthy of commemoration. However, as we all know, something went very wrong: Adam and Eve sinned, throwing everything off balance. Humanity no longer had a perfect relationship with God (Genesis 3:8-10), and our perfect harmony with creation was broken (Genesis 3:17-19, Romans 8:19-20). There was now evil in the world, and everything was not good; therefore, God had to do something to restore the relationship between Him and us, which He did by sending His Son to die for us. Through Christ�s atoning sacrifice, not only have we been redeemed, but all of creation with us also; however, we must wait for the resurrection of the dead and the glorification of our bodies at the end of time for this redemption to reach fulfillment (Romans 8:19-23).
So what does this have to do with why we worship on Sunday? Everything. Because we have been redeemed, we are a new creation (2 Corinthians 5:17, Galatians 6:15). Thus, the new, redeemed creation brought about by Christ�s redeeming sacrifice surpasses the original, damaged creation and takes its place as the event we commemorate in our weekly worship. Jesus fulfilled and perfected the original creation, and Sunday, the Lord�s Day, is the fulfillment of Saturday, the Sabbath. But why Sunday rather than Friday, the day Jesus actually offered His sacrifice?
As I said before, our redemption is not complete; we have not been fully transformed into the perfect sons of God that we are meant to be. Thus, we have not been fully changed into the new creation we will be at the resurrection of the dead (1 Corinthians 15:35-37, 42-44, 50-54). Jesus, however, has been fully transformed into a new creation; He rose in a glorified body, such as the ones we will have at the end of time (1 Corinthians 15:20, 23). He is the �first fruits� of the new creation. And He rose on a Sunday. Thus, we celebrate the new creation on Sunday, the �eighth day� (CCC 2174).
Finally, lest you think I�m reading too much into things, let�s see what the earliest Christians believed.
�On the first day of the week, when we met to break bread�� � Acts 20:7
�We keep the eighth day [Sunday] with joyfulness, the day also on which Jesus rose again from the dead� � Letter of Barnabas 15:6�8
�[T]hose who were brought up in the ancient order of things [i.e. Jews] have come to the possession of a new hope, no longer observing the Sabbath, but living in the observance of the Lord�s day, on which also our life has sprung up again by him and by his death� � Ignatius of Antioch, Letter to the Magnesians 8
�But Sunday is the day on which we all hold our common assembly, because it is the first day on which God, having wrought a change in the darkness and matter, made the world; and Jesus Christ our Savior on the same day rose from the dead� � Justin Martyr, First Apology 67
Rather than needlessly multiply the quotes, I will stop here. For more, visit Catholic Answers�s tract Sabbath or Sunday?.
There you have it. In a nutshell, both modern and original Christians worship on Sunday to commemorate Jesus� resurrection, the beginning of the new creation, so the next time a Seventh-Day Adventist asks you why we worship on Sunday rather than Saturday, you know why.
