+ Jn 20: 1-9
On the first day of the week, Mary of Magdala came to the tomb early in the morning, while it was still dark, and saw the stone removed from the tomb.
So she ran and went to Simon Peter and to the other disciple whom Jesus loved, and told them, “They have taken the Lord from the tomb, and we don’t know where they put him.”
So Peter and the other disciple went out and came to the tomb.
They both ran, but the other disciple ran faster than Peter and arrived at the tomb first;
he bent down and saw the burial cloths there, but did not go in.
When Simon Peter arrived after him, he went into the tomb and saw the burial cloths there,
and the cloth that had covered his head, not with the burial cloths but rolled up in a separate place.
Then the other disciple also went in, the one who had arrived at the tomb first, and he saw and believed.
For they did not yet understand the scripture that he had to rise from the dead.
The New American Bible
The Catechism of the Catholic Church
2174 Jesus rose from the dead “on the first day of the week.” Because it is the “first day,” the day of Christ’s Resurrection recalls the first creation. Because it is the “eighth day” following the sabbath, it symbolizes the new creation ushered in by Christ’s Resurrection. For Christians it has become the first of all days, the first of all feasts, the Lord’s Day (he kuriake hemera, dies dominica) Sunday:
We all gather on the day of the sun, for it is the first day [after the Jewish sabbath, but also the first day] when God, separating matter from darkness, made the world; and on this same day Jesus Christ our Savior rose from the dead.