Luther:

“She became the Mother of God, in which work so many and such great good things are bestowed on her as pass man’s understanding. For on this there follows all honor, all blessedness, and her unique place in the whole of mankind, among which she has no equal, namely, that she had a child by the Father in heaven, and such a Child….”

“Hence men have crowded all her glory into a single word, calling her the Mother of God…. None can say of her nor announce to her greater things, even though he had as many tongues as the earth possesses flowers and blades of grass: the sky, stars; and the sea, grains of sand. It needs to be pondered in the heart what it means to be the Mother of God.”

“God has formed the soul and body of the Virgin Mary full of the Holy Spirit, so that she is without all sins, for she has conceived and borne the Lord Jesus.”

“Christ, our Savior, was the real and natural fruit of Mary’s virginal womb… This was without the cooperation of a man, and she remained a virgin after that. […] Christ… was the only Son of Mary, and the Virgin Mary bore no children besides Him.”

“The veneration of Mary is inscribed in the very depths of the human heart.”

“Mary is the Mother of Jesus and the Mother of all of us even though it was Christ alone who reposed on her knees… If he is ours, we ought to be in his situation; there where he is, we ought also to be and all that he has ought to be ours, and his mother is also our mother.”

“[Mary is the] highest woman and the noblest gem in Christianity after Christ… She is nobility, wisdom, and holiness personified. We can never honor her enough. Still honor and praise must be given to her in such a way as to injure neither Christ nor the Scriptures.”

Calvin:

“We have already said in another place that according to the custom of the Hebrews all relatives were called ‘brethren.’ Still Helvidius [a 4th century heretic] has shown himself to be IGNORANT of this by stating that Mary had many children just because in several places they are spoken of as ‘brethren’ of Christ.” – Commentary on Matthew

[On Matt 1:25:] The inference he [Helvidius] drew from it was, that Mary remained a virgin no longer than till her first birth, and that afterwards she had other children by her husband . . . No just and well-grounded inference can be drawn from these words . . . as to what took place after the birth of Christ. He is called ‘first-born’; but it is for the sole purpose of informing us that he was born of a virgin . . . What took place afterwards the historian does not inform us . . . No man will obstinately keep up the argument, except from an extreme fondness for disputation. – IBID

“To this day we cannot enjoy the blessing brought to us in Christ without thinking at the same time of that which God gave as adornment and honour to Mary, in willing her to be the mother of his only-begotten Son.”

“There have been certain STRANGE folk who have wished to suggest from this passage [Matt 1:25] that the Virgin Mary had other children than the Son of God, and that Joseph had then dwelt with her later; BUT WHAT FOLLY THIS IS!”

Zwingli:

“I firmly believe that Mary, according to the words of the gospel as a pure Virgin brought forth for us the Son of God and in childbirth and after childbirth forever remained a pure, intact Virgin.” (Zwingli Opera, Corpus Reformatorum, Berlin, 1905, v. 1, p. 424)

“I speak of this in the holy Church of Zurich and in all my writings: I recognize MARY AS EVER VIRGIN AND HOLY.” (January 1528 in Berne, cited in Max Thurian)

“I esteem immensely the Mother of God, the ever chaste, immaculate Virgin Mary.” [E. Stakemeier, De Mariologia et Oecumenismo, K. Balic, ed., (Rome, 1962), 456].

The more the honor and love for Christ grows among men, the more esteem and honor for Mary grows, for she brought forth for us so great, but so compassionate a Lord and Redeemer. (Zwingli Opera, Corpus Reformatorum, Berlin, 1905, v. 1, pp. 427–428.)

Bullinger:

‘The Virgin Mary . . . completely sanctified by the grace and blood of her only Son and abundantly endowed by the gift of the Holy Spirit and preferred to all . . . now lives happily with Christ in heaven and is called and remains ever-Virgin and Mother of God.’

“What pre-eminence in the eyes of God the Virgin Mary had on account of her piety, her faith, her purity, her saintliness and all her virtues, so that she can hardly be compared with any of the other saints, but should by rights be rather elevated above all of them…”;

Wesley:

“I believe that He [Jesus] was made man, joining the human nature with the divine in one person; being conceived by the singular operation of the Holy Ghost, and born of the blessed Virgin Mary, who, as well after as before she brought Him forth, continued a pure and unspotted virgin.”