The doctrines set forth by the universal and ordinary magisterium are definitions of faith: "Further, by divine and Catholic faith all those things must be believed which are contained in the written word of God and in tradition, and those which are proposed by the Church, either in a solemn pronouncement or in her ordinary and universal teaching power, to be believed as divinely revealed." ( Dei Filius, D.S. 3011) Both BOB and BOD have been taught by the universal and ordinary magisterium , since the immediate post-Tridentine epoch. The post Tridentine popes have constantly and unanimously taught BOB/BOD through the organs of the ordinary magisterium.
BOD is not a new doctrine that has been introduced into the teaching of the Church. It is clearly contained in Scripture : "τoτε ἀaπεκριθη Πeτρος, Μeτι τo υδωρ δυναται κωλυσαι τις τοuόµη βαπτισθηναι τουτους οιτινες το πνευµα το αγιονελαβον ως καιἡµεις;" (Acts 10:46-7) It was not explicitly taught in the early Church but it is implicitly contained in the doctrine of BOB; since in principle and in essence it is the same as BOB, which was taught and professed ubique et ab omnibus in the early Church. Therefore, BOD is not a new doctrine in the theological sense: "Nothing new is ever added to the number of those truths which are at least implicitly contained within the deposit of revelation divinely committed to the Church." (Pius XI Mortalium Animos). Thus, the fact that BOD has only been explicitly taught by the universal magisterium after Trent is theologically of no consequence, and has no bearing on its status as a definition of the ordinary magisterium which must be believed with divine and Catholic faith.