-- Mt 7:15-20
The Holy Spirit is the protagonist, "the principal agent of the whole of the Church's mission." It is he who leads the Church on her missionary paths. "This mission continues and, in the course of history, unfolds the mission of Christ, who was sent to evangelize the poor; so the Church, urged on by the Spirit of Christ, must walk the road Christ himself walked, a way of poverty and obedience, of service and self-sacrifice even to death, a death from which he emerged victorious by his resurrection." So it is that "the blood of martyrs is the seed of Christians."
-- CCC 852