Yesterday I wrote a post on the Auckland Theology and Religious Studies blog on the exuberant use of typology in patristic and medieval biblical exegesis.
As I wrote, I was wondering about the origin of the belief that the “tau” sign in Ezekiel 9:4 was a type of Jesus’s cross. Unlike some of the other types in Scripture, this one’s not “authorised” by a typological connection in the New Testament.
In other words, it’s the kind of typology with which later Protestant exegetes would not have been very comfortable.
Anyway, I typed “lex moysi tau” into Google (law of moses tau), and eventually hit the/a jackpot with Roger Pearse’s online edition of Tertullian’s Adversus Judaeos (Against the Jews) written in 207/08.
In a frantic bid to prove that Christianity is right, Tertullian produces (to modern eyes) a rather strange collection of wooden and cross-shaped objects from the Old Testament.
So Adversus Judaeos 11 (English translation here) seems to be a source (if not the source) for the later Medieval reading of Ezekiel 9:4.
Chapter 13 also seems to be a source for the Medieval iconography that shows Isaac carrying wood in the shape of a cross as he climbs Mount Moriah on his way to be sacrificed there by his father Abraham (Genesis 22:3-7).
Isaac carrying his crossed sticks can be seen in the bottom left panel of the “New Covenant” window from the Cathedral of Saint Stephen in Bourges (early 13th cent.)
This post has no moral or conclusion beyond the fact that I find this kind of pointless, dilettante antiquarianism as rewarding as other people find doing the cryptic crossword or spotting trains.