Which Day Is the Seventh Day?

The seventh day of the week as described in the Bible is from sunset Friday to sunset Saturday night. This fact is widely understood, certainly by Judaism and by churches such as the Seventh-day Adventists and various Church of God groups, but also by the Roman Catholic Church and religious scholars of every stripe.

The weekly cycle has been consistent from creation week till now. God reiterated the seventh-day Sabbath with the miracle of manna during the Exodus from Egypt (Exodus 16:22-30), and Jesus Christ confirmed that the cycle was unbroken during His ministry since He kept the same day the Jews did.

In the nearly 2,000 years since, the Jews have faithfully remembered the seventh-day Sabbath in all parts of the globe where they were scattered.

There is no doubt that Saturday is the biblical seventh day.

ISO 8601

But there are developments that will make it harder for future generations to recognize that Saturday is the seventh day of the week. For example, consider ISO 8601, which standardizes how dates are represented and communicated by computers.

According to the International Organization for Standardization website, “ISO 8601 describes an internationally accepted way to represent dates and times using numbers.”

This is, of course, necessary to allow clear communication. As the ISO website says, “When dates are represented with numbers they can be interpreted in different ways. For example, 01/05/12 could mean January 5, 2012, or May 1, 2012. … ISO 8601 tackles this uncertainty by setting out an internationally agreed way to represent dates: YYYY-MM-DD.”

That’s all great. But the standard also numbers the weeks of the year, and to do that, they had to agree on when to start the week. And they chose Monday. So using this system, Saturday would be the sixth day of the week—which does not reflect the biblical numbering.

European calendars

In addition, many calendars in Europe show Monday as the first day of the week. This, too, makes it more confusing for Bible readers in Europe to recognize the true seventh day of the week.

Was time lost earlier?

But many wonder, why does it matter? Some think that the weekly cycle was lost long ago, and so any changes today don’t matter.

For example, some mention a miraculous event from the book of Joshua that they think would have interrupted the weekly cycle.

What about Joshua’s long day?

Joshua 10:13 records a famous miracle: “So the sun stood still in the midst of heaven, and did not hasten to go down for about a whole day.”

Could this miracle have changed the weekly cycle? One biblical scholar explains, “The miraculous lengthening of the day which provided Joshua and his army additional time for the total destruction of the enemies of Israel did not disrupt the seven-day cycle because no new calendric day was gained or lost. The only alteration was the lengthening of the daylight time of one day” (Samuele Bacchiocchi, The Sabbath in the New Testament, pp. 147-148).

Jesus Christ—the Lord of the Sabbath (Mark 2:28)—kept the same Sabbath day the Jews of His time were keeping. This confirms that nothing changed the weekly cycle up to that time. And the Jews continue to keep the same seventh day today. The biblical definition of a day is from sunset to the next sunset, not some number of hours or minutes. So, even a long day would just be counted as a day. And the God who performed the miracle could certainly make sure that His people could know when His Sabbath was.

And, as mentioned at the beginning of this article, Jesus Christ—the Lord of the Sabbath (Mark 2:28)—kept the same Sabbath day the Jews of His time were keeping. This confirms that nothing changed the weekly cycle up to that time. And the Jews continue to keep the same seventh day today.

Jews preserved knowledge of the seventh day

The apostle Paul explained that God had given certain responsibilities to the Jews. In Romans 3:1-2 he wrote, “What advantage then has the Jew, or what is the profit of circumcision? Much in every way! Chiefly because to them were committed the oracles of God.”

The word oracles is translated from the Greek logia, meaning “words,” a reference to the Hebrew and Aramaic Scriptures we know as the Old Testament. God entrusted the sacred writings of the first two-thirds of the Bible to the Jews, for them to preserve and pass on for His people down through the ages.

It would seem fair to conclude that if God entrusted the sacred writings to the Jews, He would also entrust them to correctly construct and preserve a calendar to allow His people to obey one of the most important aspects of His law—the keeping of holy time. This includes the weekly Sabbath and the annual Sabbaths outlined in Leviticus 23 and observed by Jesus, the apostles and the New Testament Church. (For more about the annual festivals and their meaning, see our booklet From Holidays to Holy Days: God’s Plan for You.)

History and names of days help confirm the Saturday Sabbath

In many European languages, the names of the days of the week are directly related to the Roman names, most of which were named for Roman gods.

Oxford Words blog points out that Saturday actually had two names: “With Saturday, the classical Latin dies Saturnī (Saturn’s Day) gave way to the later form dies Sabbati (the Sabbath day).” This later form has been transformed into the Spanish sábado, the Italian Sabato, the French samedi and even the German Samstag.

So even this etymology adds confirmation to Saturday being the seventh day of the week—the Sabbath.

Catholics agree

Yet most Protestant churches continue to meet on Sunday, following the millennia-old tradition of the Catholic Church. However, the Catholic Church recognizes that the change from Saturday to Sunday was not made in the Bible. They point to the authority of their church to make the change, not the Bible.

In its section on the “Ten Commandments,” the Catholic Encyclopedia says: “The Church, on the other hand, after changing the day of rest from the Jewish Sabbath, or seventh day of the week, to the first, made the Third Commandment [we count it as the Fourth] refer to Sunday as the day to be kept holy as the Lord’s Day.”

You can read more about this in our articles “Was the Sabbath Changed to Sunday?” “Did the Early Christians Worship on Sunday?” and “When and How Did the Change in Worship From Saturday to Sunday Occur?”

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Biblical seventh day continues

The biblical seventh-day Sabbath continues, and the knowledge of which day it is has been preserved by the Jews. The Sabbath has never been lost, yet the importance of this gift from God has been overlooked or misunderstood by most Christian churches today.

However, you can enjoy the benefits and learn the lessons of God’s holy Sabbath. You can remember it and keep it holy as God commanded. Learn more about it in our informative free booklet The Sabbath: A Neglected Gift From God.