Apostolate: The activity of the Christian which fulfills the apostolic nature of the whole Church by working to extend the reign of Christ to the entire world. (Catechism of the Catholic Church 863)
Christ has no body now on earth but yours,
no hands but yours, no feet but yours.
Yours are the eyes through which Christ's compassion
is to look out to the world.
Yours are the feet with which Christ
is to go about doing good.
Yours are the hands with which Christ
is to bless all the people now.
St. Teresa of Avila
Witnessing Through Service
"See how they love one another!" is what the ancient pagans said of the early Christians, whose charity moved the hearts of those around them [Tertullian, Apologeticum, ch. 39, 7]. It sparked an interest in finding what exactly enabled them to love one another. So it is that charity--our faith in action--evangelizes others today.
As children of God and followers of Christ, we seek opportunities for acts of charity, for living out our faith in concrete ways. Expressing the love of the Gospel through our actions is vital to being faithful disciples of Jesus and His authentic witnesses. "Faith of itself, if it does not have works, is dead" [James 2:17]. We can do this on our own or through the many Christian organizations doing valuable and visible works of service for the Glory of God and the welfare of our brothers and sisters . . . . (Most Rev. Paul S. Loverde, Bishop of Arlington, Go Forth With Hearts on Fire, Nov. 24, 2013, 27)