In the waters of Baptism, we have been "washed . . . Sanctified . . . Justified in the name of the Lord Jesus Christ and in the Spirit of our God." Our Father calls us to holiness in the whole of our life, and since "he is the source of (our) life in Christ Jesus, who became for us wisdom from God, and . . .sanctification," both his glory and our life depend on the hallowing of his name in us and by us. Such is the urgency of our first petition.
By whom is God hallowed, since he is the one who hallows? But since he said, "You shall be holy to me; for I the LORD am holy," we seek and ask that we who were sanctified in Baptism may persevere in what we have begun to be. And we ask this daily, for we need sanctification daily, so that we who fail daily may cleanse away our sins by being sanctified continually.... We pray that this sanctification may remain in us.
Source: Catechism of the Catholic Church (Vatican.va)