"However, an apostolate of this kind does not consist only in the witness of one's way of life; a true apostle looks for opportunities to announce Christ by words. . . ."
"Apostolatus tamen huiusmodi non in solo vitae testimonio consistit; verus apostolus quaerit occasiones Christum verbis annuntiandi. . . ."
Paul VI, Apostolicam actuositatem (1965) 6.3. I was put onto this by CCC 905.