In the Catholic Church, Advent is a period of preparation extending over the four Sundays before Christmas. The word Advent comes from the Latin advenio, "to come to," and refers to the coming of Christ. And the term the coming includes three references: first of all, to our celebration of Christ's birth at Christmas; second, to the coming of Christ in our lives through grace and the Sacrament of Holy Communion; and finally, to his second coming at the end of time.
Our preparations, therefore, should have all three comings in mind. We need to prepare our souls to receive Christ worthily.