Mr. Albrecht correctly recognizes that the following quotation does not teach the immaculate conception of Mary:
He [Pelagius] then enumerates those “who not only lived without sin, but are described as having led holy lives,—Abel, Enoch, Melchizedek, Abraham, Isaac, Jacob, Joshua the son of Nun, Phinehas, Samuel, Nathan, Elijah, Joseph, Elisha, Micaiah, Daniel, Hananiah, Azariah, Mishael, Mordecai, Simeon, Joseph to whom the Virgin Mary was espoused, John.” And he adds the names of some women,—“Deborah, Anna the mother of Samuel, Judith, Esther, the other Anna, daughter of Phanuel, Elisabeth, and also the mother of our Lord and Saviour, for of her,” he says, “we must needs allow that her piety had no sin in it.” We must except the holy Virgin Mary, concerning whom I wish to raise no question when it touches the subject of sins, out of honour to the Lord; for from Him we know what abundance of grace for overcoming sin in every particular was conferred upon her who had the merit to conceive and bear Him who undoubtedly had no sin.Augustine, On Nature and Grace, Chapter 42.
Mr. Albrecht, however, insists that it does teach that Augustine believed that Mary was free from personal sin. This is not the case, as we discover from other things that Augustine taught. For example, Augustine clearly stated:
For to speak more briefly, Mary who was of Adam died for sin, Adam died for sin, and the Flesh of the Lord which was of Mary died to put away sin.Augustine, Sermon 2 on Psalm 35, Section 3.
How then shall we interpret the issue of the first quotation? Augustine simply does not want to criticize Mary the Mother of our Lord (Augustine never, to my knowledge, refers to her by the name "Mother of God") for her sin. He does not want to take up the question out of respect for Jesus.
Does that mean he concedes the matter to the Pelagians who proposed that Mary was sinless? Of course not. Just because a person does not take up a question is not a concession, particularly when the reason they give is unrelated to the issue, unless one imagines that the reason is an excuse.
Thus, we can see that actually while Mr. Albrecht is wise not suggest that the passage establishes the view of the immaculate conception of Mary, it does not even establish that Augustine believed in the personal sinlessness of Mary.
Mr. Albrecht seems to think that there is plenty of patristic evidence of early teachings of the immaculate conception. However, it does not appear that there is any clear teaching in that regard prior to the Pelagians, and there does not appear to have been widespread acceptance of that error when the Pelagians first tried to introduce it. Perhaps, in an upcoming video, Mr. Albrecht will set forth the evidence he believes exists in the church fathers for the doctrine of the immaculate conception. If so, I - for one - will be very interested to review what he says.
I completed the above, but there was still a nagging thought in my head asking my why Mr. Albrecht had come to the conclusion he did about it being about personal sin versus original sin. Well, it turns out that Aquinas quotes (with approval) from Augustine, and particularly from this work. Aquinas' interpolated copy, however, has an interesting addition after "... her who had the merit to conceive and bear Him who undoubtedly had no sin," Aquinas' quotation adds: "Christ excelled the Blessed Virgin in this, that he was conceived and born without original sin. The Blessed Virgin was conceived in original sin, but not born in it." (Aquinas, On the Angelic Greeting) However, this addition is not original to Augustine is not included in Migne's edition of Augustine's works. It should be noted that some editors have simply attributed these sentences directly to Aquinas as his quotation on the text, and it may not be entirely clear since quotation marks were not used, whether Aquinas was intending to quote Augustine or was simply adding his own commentary. In other words, my own comments above about Aquinas' bad copy of Augustine may better (or alternatively) ascribed to the editors of Aquinas' work. Either way, the main point that Aquinas - like the Reformed churches - regarded Mary as having been conceived with original sin, remains.