When a bishop acts in persona Christi, fulfilling his duty to teach on matters of
faith and morals by identifying propositions to which he calls upon the faithful to assent, he presumably means to state truths that belong to one
and the same body of truths: primarily, those entrusted by Jesus to his Church
and, secondarily, those necessary to preserve the primary truths as inviolable
and / or to
expound them with fidelity.