Joseph's Ignorance

Quid autem praejudicat Mariae, si coelestis consilii mysterium Joseph non intellexit, et putavit virginem non esse, quam praegnantem videret? Resurrectionem ejus angeli ignoraverunt, quod significant versiculi: Tollite portas, principes, vestras, et elevamini portae aeternales, et introibit Rex gloriae. Quis est iste Rex gloriae? Interrogant quasi ignorent; et alii respondent: Dominus fortis et potens, Dominus potens in praelio, ipse est Rex gloriae. Et repetivit Propheta eosdem versiculos, et nihilominus illi quasi ignorantes iterum interrogaverunt; sic enim scriptum est: Tollite portas, principes, vestras, et elevamini portae aeternales, et introibit Rex gloriae. Quis est iste Rex gloriae? Quomodo ergo homo potuit divinum scire secretum, quod angeli nesciebant? Et in Esaiae libro habes: Quis est iste, qui advenit ex Edom; rubor vestimentorum ejus ex Bosor? Et utique minus erat hominem resurrexisse, quam virginem parturisse. Etenim jam Eliae precibus, Elisaei orationibus mortui resurrexerant: numquam autem ante numquam postea virgo generavit. Hoc autem opinatus est quod traduceret eam quasi ream, antequeam ab angelo moneretur: postea autem quasi fidelis nec dubius virginitatis ejus servavit oraculum. Sanctus Ambrosius Mediolanensis, De Institutione Virginis Et Sanctae Mariae Virginitate Perpetua, Caput V Source: Migne PL 16.315c-316b

Now why did Joseph prejudge Mary so unless he did not understand the mystery of the heavenly plan, and he deemed that her whom he saw pregnant was not a virgin? 1 That the angels were ignorant of His resurrection the lines tell us: 'Lift up your gates, princes, and raise up your eternal gates, and the king of glory shall enter. Who is the king of glory?' And they ask this as those who do not know, and the others reply: 'The Lord strong and powerful, The Lord mighty in battle, He is the king of glory.' 2 And the Prophet repeats the same lines, and nevertheless they, as if ignorant, ask again, for so it is written: 'Lift up your gates, princes, and raise up your eternal gates, and the king of glory shall enter. Who is the king of glory?' 3 How, then, is a man able to know the Divine mystery which angels do not know? In the book of Isaiah you have: 'Who is this, who comes from Edom, with vestments of red from Bosor?' 4 And a lesser thing was the resurrection of a man than a virgin giving birth. For already the prayers and petitions of Elisha had raised the dead, 5 but never before and never after did a virgin give birth. Thus he thought to convict her as guilty before he was admonished by the angel. And after that as one faithful, not doubting her virginity, he guarded the oracle. Saint Ambrose, on The State of The Virgin And The Perpetual Virgnity of Saint Mary, Chapter 5 1 Mt 1.18-19 2 Ps 23.7-8 3 Ps 23. 9-10 4 Isaiah 63.1 5 3 Kings 17.22