Every so often Protestants suggest that the Church’s ecclesiology basically forbids Catholic laymen from professing or defending their faith, but this suggestion is mistaken. It’s worth acknowledging that this may be an entirely innocent misunderstanding. For example, in a recent episode we saw that the Catechism emphasizes the importance of authorized teachers. So how can it be that laymen would be free to publicly defend the faith?
We can do this because the Church says that we may do so (and that we should).
Those who with God’s help have welcomed Christ’s call and freely responded to it are urged on by love of Christ to proclaim the Good News everywhere in the world. This treasure, received from the apostles, has been faithfully guarded by their successors. All Christ’s faithful are called to hand it on from generation to generation, by professing the faith, by living it in fraternal sharing, and by celebrating it in liturgy and prayer. [CCC §3, emphasis added]
The same is taught by the second Vatican Council; in fact, one of the Council’s decrees is dedicated to the subject: Apostolicam Actuositatem. Among many other things, it says this:
3. The laity derive the right and duty to the apostolate from their union with Christ the head; incorporated into Christ’s Mystical Body through Baptism and strengthened by the power of the Holy Spirit through Confirmation, they are assigned to the apostolate by the Lord Himself. They are consecrated for the royal priesthood and the holy people (cf. 1 Peter 2:4-10) not only that they may offer spiritual sacrifices in everything they do but also that they may witness to Christ throughout the world. …
6. … Since, in our own times, new problems are arising and very serious errors are circulating which tend to undermine the foundations of religion, the moral order, and human society itself, this sacred synod earnestly exhorts laymen-each according to his own gifts of intelligence and learning-to be more diligent in doing what they can to explain, defend, and properly apply Christian principles to the problems of our era in accordance with the mind of the Church.
So we see that Catholic laymen have a duty to proclaim and defend the faith which is theirs by virtue of their union with Christ through Baptism, and that the Church “earnestly exhorts” them to fulfill that duty. But we’re not free to say just anything we want, of course. We must fulfill this duty in accordance with truth, obviously, and that’s what the Council means when it says that we must do so in accordance with the mind of the Church.