Evangelii Nuntiandi §41

41. Without repeating everything that we have already mentioned, it is appropriate first of all to emphasize the following point: for the Church, the first means of evangelization is the witness of an authentically Christian life, given over to God in a communion that nothing should destroy and at the same time given to one's neighbor with limitless zeal. As we said recently to a group of lay people, "Modern man listens more willingly to witnesses than to teachers, and if he does listen to teachers, it is because they are witnesses."[67] St. Peter expressed this well when he held up the example of a reverent and chaste life that wins over even without a word those who refuse to obey the word.[68] It is therefore primarily by her conduct and by her life that the Church will evangelize the world, in other words, by her living witness of fidelity to the Lord Jesus- the witness of poverty and detachment, of freedom in the face of the powers of this world, in short, the witness of sanctity.

67. Pope Paul VI, Address to the Members of the Consilium de Laicis (2 October 1974): AAS 66 (1974), p. 568.

68. Cf. 1 Pt 3:1.