Here is a question that stumps a lot of Christians:

The Ten Commandments say to keep the Sabbath holy.

The Sabbath is Saturday.

So why does almost every Christian church worship on Sunday?

Did someone change the commandments?

Wait… Who Moved the Sabbath to Sunday?

Some people believe:

“The Sabbath was always Saturday. Christians changed it to Sunday centuries later, maybe because of the Emperor Constantine.”

And at first that sounds possible.

The Bible never says, “The Sabbath has moved to Sunday.”

And Constantine did make Sunday a day of rest in the Roman Empire in A.D. 321.

But then you read the New Testament and the first Christians, and you have to stop for a second.

Because Christians were gathering on Sunday 250 years before Constantine.

Jesus Rose on the First Day

All four Gospels say Jesus rose from the dead on the first day of the week (Matthew 28:1; Mark 16:2; Luke 24:1; John 20:1).

Sunday.

That same evening, He appeared to the Apostles (John 20:19).

And eight days later, the next Sunday, He appeared to them again, with Thomas (John 20:26).

And the Holy Spirit came down at Pentecost, fifty days after Passover, on a Sunday.

God kept doing His biggest things on the first day of the week.

The First Christians Gathered on Sunday

“And on the first day of the week, when we were assembled to break bread, Paul discoursed with them,”
— Acts 20:7

Paul told the Corinthians to set aside their collection “on the first day of the week” (1 Corinthians 16:2).

And St. John wrote:

“I was in the spirit on the Lord’s day, and heard behind me a great voice, as of a trumpet,”
— Revelation 1:10

The Lord’s Day.

A new name for a new day.

What About the Sabbath?

The Sabbath was a sign of the Old Covenant, given to Israel (Exodus 31:13).

It remembered God resting after creation.

Paul told the Colossians not to let anyone judge them about “a festival day, or of the new moon, or of the sabbaths,” because these were a shadow of things to come, and the reality is Christ (Colossians 2:16–17).

Sunday does not erase the Sabbath.

It fulfills it.

The Sabbath celebrated the first creation.

Sunday celebrates the new creation, when Jesus rose and made all things new.

Then You Read the First Christians

Around A.D. 107, St. Ignatius of Antioch wrote that those who had lived under the old ways had come to a new hope, no longer keeping the Sabbath, but living according to the Lord’s Day, the day our life rose through Him.

The Letter of Barnabas, written around A.D. 100, calls Sunday “the eighth day,” the beginning of a new world, the day Jesus rose.

The Didache tells Christians to gather on the Lord’s Day to break bread and give thanks.

And around A.D. 155, St. Justin Martyr explained why Christians gather on Sunday: it is the first day, when God made the world, and the day Jesus Christ rose from the dead.

None of these men had ever heard of Constantine.

He wasn’t born yet.

Why Did the Church Make It Official?

As the Church spread among Gentiles, the question came up: should Christians also keep the Jewish Sabbath?

Around A.D. 364, the Council of Laodicea told Christians to honor the Lord’s Day and rest on it if possible.

The Church did not invent Sunday worship.

She protected what Christians had done since the Resurrection.

So What Is the Catholic Claim?

Here it is in simple terms.

Jesus rose on the first day of the week, appeared to the Apostles on Sundays, and sent the Holy Spirit on a Sunday.

The first Christians gathered on the first day of the week to break bread and called it the Lord’s Day.

Ignatius, Barnabas, the Didache, and Justin all describe Sunday worship long before Constantine.

The Sabbath was fulfilled in Christ, and Sunday celebrates the new creation.

The Catechism says Sunday fulfills the spiritual truth of the Sabbath (CCC 2175).

So the real question is not:

“Who changed the Sabbath to Sunday?”

The better question is:

“What happened on Sunday that changed everything?”

Because the tomb was empty on the first day of the week.

And Christians have been celebrating ever since.

Keep reading: Why Catholics Go to Mass on Sunday, or browse more questions in Catholicism Explained.

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Catholic Sources

Scripture (Douay-Rheims): Exodus 20:8–11; Exodus 31:13; Matthew 28:1; Mark 16:2, 9; Luke 24:1; John 20:1, 19, 26; Acts 2:1; Acts 20:7; 1 Corinthians 16:2; Colossians 2:16–17; Revelation 1:10.

Catechism of the Catholic Church: CCC 2174–2176 (the Lord’s Day fulfills the Sabbath).

Early Christian writers: The Didache 14 (late first century); Letter of Barnabas 15 (c. A.D. 100); St. Ignatius of Antioch, Letter to the Magnesians 9 (c. A.D. 107); St. Justin Martyr, First Apology 67 (c. A.D. 155).

Church documents: Council of Laodicea, canon 29 (c. A.D. 364); Pope St. John Paul II, Dies Domini (1998).

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