"The title Theotocos, or Mother of God, was familiar to Christians from primitive times, and had been used, among other writers, by Origen, Eusebius, St. Alexander, St. Athanasius, St. Ambrose, St. Gregory Nazianzen, St. Gregory Nyssen, and St. Nilus. She had been called Ever-Virgin by others, as by St. Epiphanius, St. Jerome, and Didymus. By others, 'the Mother of all living,' as being the antitype of Eve; for, as St. Epiphanius observes, 'in truth,' not in shadow, 'from Mary was Life itself brought into the world, that Mary might bear things living, and might become Mother of living things.'St. Augustine says that all have sinned 'except the Holy Virgin Mary, concerning whom, for the honour of the Lord, I wish no question to be raised at all, when we are treating of sins.' 'She was alone and wrought the world's salvation,' says St. Ambrose, alluding to her conception of the Redeemer. She is signified by the Pillar of the cloud which guided the Israelites, according to the same Father; and she had 'so great grace, as not only to have virginity herself, but to impart it to those to whom she came;'—'the Rod out of the stem of Jesse,' says St. Jerome, and 'the Eastern gate through which the High Priest alone goes in and out, yet is ever shut;'—the wise woman, says St. Nilus, who 'hath clad all believers, from the fleece of the Lamb born of her, with the clothing of incorruption, and delivered them from their spiritual nakedness;'—'the Mother of Life, of beauty, of majesty, the Morning Star,' according to Antiochus;—'the mystical new heavens,' 'the heavens carrying the Divinity,' 'the fruitful vine by whom we are translated from death unto life,' according to St. Ephraim;—'the manna which is delicate, bright, sweet, and virgin, which, as though coming from heaven, has poured down on all the people of the Churches a food pleasanter than honey,' according to St. Maximus.
St. Proclus calls her 'the unsullied shell which contains the pearl of price,' 'the sacred shrine of sinlessness,' 'the golden altar of holocaust,' 'the holy oil of anointing,' 'the costly alabaster box of spikenard,' 'the ark gilt within and without,' 'the heifer whose ashes, that is, the Lord's Body taken from her, cleanses those who are defiled by the pollution of sin,' 'the fair bride of the Canticles,' 'the stay ([sterigma]) of believers,' 'the Church's diadem,' 'the expression of orthodoxy.' These are oratorical expressions; but we use oratory on great subjects, not on small. Elsewhere he calls her 'God's only bridge to man;' and elsewhere he breaks forth, 'Run through all creation in your thoughts, and see if there be equal to, or greater than, the Holy Virgin Mother of God.' "
- Venerable John Henry Newman, C.O., An Essay on the Development of Christian Doctrine