aragonsr. You asked,
This sounds like the common folk preached (in Acts 8:4). But I thought that Jesus only gave that authority to the apostles and their successors. (I forget the verse)
But this is not a dichotomy. In a sense there is “preaching” by both the clergy and laity.
The clergy in a Liturgical sense. Go back and re-read the books of Ezra and Nehemiah and you will see this being carried out Liturgically by the Priests.
But this doesn’t mean the Israelites cannot evangelize one another about God. In a certain sense they had to “evangelize” their pagan wives that some of them took (by telling them they were not allowed to be “married” to them).
Likewise in the Church (fulfilled Judaism) today too. It is not an “either/or” motif.
Maybe this will help you in your understanding (bold mine):
CCC 941 Lay people share in Christ’s priesthood: ever more united with him, they exhibit the grace of Baptism and Confirmation in all dimensions of their personal family, social and ecclesial lives, and so fulfill the call to holiness addressed to all the baptized.
CCC 942 By virtue of their prophetic mission, lay people “are called . . . to be witnesses to Christ in all circumstances and at the very heart of the community of mankind” (GS 43 # 4).
CCC 943 By virtue of their kingly mission, lay people have the power to uproot the rule of sin within themselves and in the world, by their self-denial and holiness of life (cf. LG 36).