The Catechism in Questions & Answers

386. Where are the four characteristics of the church of Jesus Christ manifest?

The four characteristics of the church of Jesus Christ—oneness, holiness, universality, and apostolicity—are manifest in different ways and to varying degrees in the various Christian denominations.
These identifying features of the church of Jesus Christ are most clearly manifest where the Apostles are at work: they dispense the three sacraments to the living and the dead and proclaim the word of God with emphasis on the imminent return of Christ. It is here that the Lord’s work of redemption is established.

The term ‘Lord’s work of redemption’ is generally understood in reference to Jesus’ saving act, which has already been completed. When this term is used here, it refers to that part of the church in which Apostles are active in imparting those gifts of salvation that serve to the preparation of the firstlings, the bride of Christ.