This teaching requires definitive assent, since, founded on the written Word of God, and from the beginning constantly preserved and applied in the Tradition of the Church, it has been set forth infallibly by the ordinary and universal Magisterium (cf. Second Vatican Council, Dogmatic Constitution on the Church Lumen Gentium 25, 2). Thus, in the present circumstances, the Roman Pontiff, exercising his proper office of confirming the brethren (cf. Lk 22:32), has handed on this same teaching by a formal declaration, explicitly stating what is to be held always, everywhere, and by all, as belonging to the deposit of the faith.