You have probably never thought of it this way, but every time Christians gather for worship on a Sunday morning, they are making a historical claim. Not a vague spiritual gesture, but a specific, verifiable assertion rooted in a particular event on a particular day: the resurrection of Jesus Christ from the dead on the first day of the week. Sunday worship is not merely a Christian tradition. It is a piece of resurrection evidence.
This point is frequently overlooked in discussions of the resurrection’s historical credibility, and that is a significant oversight. The universal, unbroken Christian practice of assembling for worship on Sundays is one of the most durable and widely distributed facts connected with the earliest history of the church. And it admits of only one coherent explanation.
The Strangeness of Sunday
To grasp the historical weight of Sunday observance, we must understand how unusual it was. The early Christians were, almost without exception, Jewish. And for Jews, the sacred day of weekly rest and worship was the Sabbath — Saturday, the seventh day, commemorating God’s rest after creation (Exod 20:8–11). There was no precedent in Jewish practice for treating Sunday as a holy day. There is no known instance in the ancient world of Sunday being considered a weekly sacred day outside of Christianity.
Yet from the very earliest days of the church, all Christian communities of which there is record gathered on “the first day of the week” (Acts 20:7; 1 Cor 16:2). So deeply embedded was this practice that Sunday came to be universally called “the Lord’s Day” (Rev 1:10) — a phrase that almost certainly originated with the Twelve Apostles themselves. This was not a later development or a convenient accommodation to the Roman work calendar. It was the founding practice of the Christian community.
Why Sunday? The Only Coherent Answer
The question that demands explanation is: why Sunday? Why did a community of Jewish believers abandon the Sabbath as their primary day of assembly and substitute a day of the week with no prior religious significance? The New Testament answers this directly and consistently: because the resurrection occurred on the first day of the week.
All four Gospels record that the tomb was found empty “on the first day of the week” (Matt 28:1; Mark 16:2, 9; Luke 24:1; John 20:1, 19). The first appearances of the risen Christ occurred on that same Sunday. Sunday therefore became the day of distinctively Christian significance — the day of resurrection, of new creation, of the new age breaking into the old. As one scholar observes: “The Eucharist was celebrated on a Sunday (and Sunday had theological significance) from the first years of Christianity because Christians believed that the central Christian event of the Resurrection occurred on a Sunday.”1
The Third Day
Sunday is also “the third day” — a phrase that Jesus himself used repeatedly before his crucifixion to predict his resurrection (Matt 16:21; 17:23; 20:19; Luke 24:45–46). Against a possible background in the feast of firstfruits (Lev 23:9–14), and drawing on Hosea 6:2, the “third day” carried profound theological freight. Jewish counting was inclusive: the crucifixion on Friday was day one, the Sabbath was day two, and Sunday was day three.
How did the disciples unanimously come to place the resurrection on the third day unless something decisive happened on that specific day? As Bavinck observed, “merely attributing this to Old Testament predictions or to mythology fails the test of plausibility. Something must have happened on that third day for the disciples to situate it unanimously on that day.”2 The simplest and most historically satisfying explanation is that it actually happened on that day.
Every Sunday, then, is the Lord’s Day. Not only Easter Sunday — every Sunday. The entire weekly cycle of Christian worship, stretching unbroken across two millennia and every continent, is testimony to a single irreversible event. The tomb was empty on the first day of the week. And the community that discovered it has never forgotten.