This is the day which the LORD has made; let us rejoice and be glad in it. 103
Catechism number 2174
Jesus rose from the dead "on the first day of the week."104 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,105 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:
Sunday - fulfillment of the sabbath