Which day is the Biblical Sabbath? Can we know with certainty that it has not been changed?
From the beginning, God makes it clear that the seventh day is the Sabbath of the Lord (Genesis 2:1–3; Exodus 20:11), so we don’t need to be confused over which day of the week should be observed as the Sabbath. The weekly cycle has never changed since Creation, because there has always been a seven-day cycle; so we can be certain that the day is—and has always been—Saturday.
The Bible helps us see this clearly: Jesus died on the sixth day, known in Scripture as the “preparation day” (John 19:31). Christianity has celebrated this historical day as “Good Friday.” The Bible also makes it clear that Jesus was resurrected from the grave on the first day of the week (Matthew 28:1–6; John 20:1). In fact, Matthew 28:1 says, “After the Sabbath, as the first day of the week began to dawn….” So, Jesus was resurrected after the Sabbath, on the first day of the week; and Christianity correctly recognizes this historic day as “Resurrection Sunday.”
So if Jesus died on preparation day (Friday) and resurrected on the first day (Sunday), then that means Jesus rested in the tomb on the weekly seventh-day Sabbath—Saturday.
Calendars have never been altered or changed in the past in such a way as to affect the weekly cycle. In other words, the weekly cycle—beginning with the first day—has always ended with the seventh day since the beginning of Creation. While other cultures created their own version of the weekly cycle throughout history, the Jewish nation has never lost sight of the biblical weekly cycle. There have also been calendar days that have been omitted in the past, but this did not affect the succession of the days of the week.
The names of the days of the week can be traced back to ancient Babylonians who were the first to name them after their planetary gods. Later, this custom was adopted by the Romans with the institution of the Julian Calendar in the first century B.C. The Romans named the first day of the week after their sun god, hence Sunday, which they deemed the most important of them all. The second day of the week was named after their moon god, hence Monday. While the pagan Romans adopted an eight-day “nundinal cycle” in ancient times, the Jewish nation still simultaneously recognized and practiced a seven-day weekly cycle within their culture.
Then, in AD 321, the Roman government adopted a seven-day weekly cycle, and the Roman Emperor Constantine officially acknowledged the Judeo-Christian week, making Sunday the first day of the week, and recognizing Saturday as the seventh day of the week. Again, the weekly cycle was the same one Jesus acknowledged nearly 300 years before; the only difference was that the days were given pagan names based on Roman and Teutonic Mythology. The conclusion of the matter settles on the fact that, since Creation, there has always been a successive, seven-day weekly cycle.
The fact that God commanded His people to “remember the Sabbath day” is a powerful point in and of itself (Exodus 20:8). Would God have allowed an entire nation of people to forget the day He instructed them to remember? We can be certain that the seventh-day Sabbath (Saturday) that Jesus kept Holy is the same seventh-day Sabbath we have today. In fact, the United States Naval Observatory was able to confirm this point after researching the matter themselves in this document from 1932:
We can be reassured that we serve a powerful God who will not allow us to forget and lose sight of the blessings of His Sabbath. Even through secular institutions, He’s able to remind the world that His ways are everlasting and unchanging.
The world may deny it; the occasional Christian pastor may even try to blot it out; however, the truth is clear and unavoidable: the Sabbath is the seventh day, and that seventh day happens to be what both history and our calendar call Saturday.
Although given a man-made title in English, may it never be forgotten that the Sabbath was instituted by God to be remembered, observed, and kept holy on the seventh day by all mankind (Mark 2:27–28).