Gate And Vessel And Cloud

Ipse ergo rex Israel transivit hanc portam, ipse dux sedit in ea; quando Verbum caro factum est, et habitavit in nobis, quasi Rex sedens in aula regali uteri virginalis, vel in olla ferventi, sicut scriptum est: Moab aula spei, vel olla spei meae. Utrumque enim diversis in codicibus invenitur. Aula regalis est virgo, quae non est viro subdita, sed Deo soli. Est et olla uterus Mariae, quae Spiritu ferventi qui supervenit in eam, replevit orbem terrarum, cum perperit Salvatorem. Qui manducavit in porta sedens, utique cibum illum de quo dicit: Meus cibus est ut faciam voluntatem Patris mei qui in coelo est. O divitias Marianae virginitatis. Quasi olla ferbuit, et quasi nubes pluit in terras gratiam Christi; scriptum est enim de ea: Ecce Dominus venit sedens super nubem levem. Vere levem quae conjugii onera nescivit: vere levem, quae levavit hunc modum de gravi foenore peccatorum. Levis erat, quae remissionem peccatorum utero gestabat. Denique levavit Joannem in utero constitutum, qui ad vocem ejus exsilivit, et infans exsultavit in gaudio, prius sensu devotionis quam spiritus infusione vitalis animatus. Sanctus Ambrosius Mediolanensis, De Institutione Virginis et Sanctae Mariae Virginitate Perpetua ad Eusebium, Caput XII-XIII Source: Migne PL 16 324c-325b

Therefore the King of Israel Himself passed through this gate, the leader himself sat there, 1 when 'The Word was made flesh and dwelt among us,' 2 as the king sitting in the chamber of the royal womb of the Virgin, or in a heated vessel, as it is written, 'Moab is the chamber of my hope,' or 'the vessel of my hope,' 3 both variants being found in the books. The royal chamber is the Virgin, she who was bound to no man, but God alone. The womb of Mary is the vessel which by the blazing Spirit who came upon her filled the orb of the earth when she bore the Saviour. He who ate sitting in this gate, 4 that food concerning which it is said, 'My food is that I do the will of my Father who is in heaven.' 5 O rich virginity of Mary! As a vessel that gives warmth, and as a cloud which rains on earth the grace of Christ, for it is written: 'Behold the Lord comes sitting on a light cloud.' 6 And truly light she was who did not know the burdens of coupling, truly light she was who lifted up this way from the heavy debt of sinners. Light she was who bore the forgiveness of sins in her womb. And then she lifted up John who was in the womb, he who quickened to her voice, an infant leaping in joy, 7 before sense being animated with the infusion of the living Spirit. Saint Ambrose, On The Birth of the Virgin and the Perpetual Virginity of Mary, to Eusebius, Chap 12-13 1 Ez 44.2-3  2 Jn 1.14  3 Ps 59.10  4 Ezek 44.3  5 Jn 4.34  6 Isaiah 19.1  7 Lk 1.41