CCC 515 The Gospels were written by men who were among the first to have the faith1 and wanted to share it with others. Having known in faith who Jesus is, they could see and make others see the traces of his mystery in all his earthly life. From the swaddling clothes of his birth to the vinegar of his Passion and the shroud of his Resurrection, everything in Jesus’ life was a sign of his mystery.2 His deeds, miracles and words all revealed that “in him the whole fullness of deity dwells bodily.”3 His humanity appeared as “sacrament”, that is, the sign and instrument, of his divinity and of the salvation he brings: what was visible in his earthly life leads to the invisible mystery of his divine sonship and redemptive mission

CCC 640 “Why do you seek the living among the dead? He is not here, but has risen.”4 The first element we encounter in the framework of the Easter events is the empty tomb. In itself it is not a direct proof of Resurrection; the absence of Christ’s body from the tomb could be explained otherwise.5 Nonetheless the empty tomb was still an essential sign for all. Its discovery by the disciples was the first step toward recognizing the very fact of the Resurrection. This was the case, first with the holy women, and then with Peter.6 The disciple “whom Jesus loved” affirmed that when he entered the empty tomb and discovered “the linen cloths lying there”, “he saw and believed”.7 This suggests that he realized from the empty tomb’s condition that the absence of Jesus’ body could not have been of human doing and that Jesus had not simply returned to earthly life as had been the case with Lazarus.8

CCC 2174 Jesus rose from the dead “on the first day of the week.”9 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,10 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.11

1 Cf. Mk 1:1; Jn 21:24.
2 Cf Lk 2:7; Mt 27: 48; Jn 20:7.
3 Col 2:9.
4 Lk 24:5-6.
5 Cf. Jn 20:13; Mt 28:11-15.
6 Cf. Lk 24:3, 12, 22-23.
7 Jn 20:2, 6, 8.
8 Cf. Jn 11:44; 20:5-7.
9 Cf. Mt 28:1; Mk 16:2; Lk 24:1; Jn 20:1.
10 Cf. Mk 16:1; Mt 28:1.
11 St. Justin, I Apol. 67: PG 6, 429 and 432.