J.B. Lightfoot wrote a commentary on the Epistle to the Galatians. My copy, a revised edition, dates to 1900. One can read it online on Archive.org:
St. Paul's Epistle to the Galatians, a Revised Text with Introduction, Notes, and Dissertations (1870)
While it is dated, I tracked down a copy due to one of the dissertations therein:
This essay is important for two main reasons:
(1) It is a sound critique of the Hieronymian view of the brothers/sisters of Jesus (the view, advocated by Jerome and most Roman Catholics, that the brothers/sisters of Jesus were near-relatives or cousins) and
(2) A defence of the Epiphanian view, wherein the brothers/sisters of Jesus were children from a previous marriage of Joseph, which is the predominant view of Eastern Orthodoxy (it should be noted that Lightfoot did not hold to the perpetual virginity of Mary).
While I disagree with the Epiphanian view, Lightfoot’s defence is one of the best I have encountered and, to be fair, his interaction with the other perspectives demonstrated much integrity in giving them a fair hearing.
Perhaps the best defence of the Epiphanian view one will encounter will be that of Laurent A Cleenewerck, Aiparthenos Ever-Virgin? Understanding the Orthodox Catholic Doctrine of the Perpetual Virginity of Mary, the Mother of Jesus, and the Identity of James and the Brothers and Sisters of the Lord
