The Epistle of Barnabas also employs another technique of ancient Jewish exegesis, that of gematria, the ascription of religious significance to the numerical value of letters. When applied to letters of the Greek alphabet, it is also called isopsephia. A well-known New Testament instance of its use is in the Book of Revelation, "Let the one who has understanding calculate the number of the beast, for it is the number of a man, and his number is 666", which is often interpreted as referring to the name "Nero Caesar" written in Hebrew characters. The interpretation of Genesis 17:23–27 in Barnabas 9:7–8 is considered "a classic example" of allegorical or midrashic interpretation: "In reading the story of Abraham circumcising his household, his eye fell on the figure 318 which appeared in the scroll as ΤΙΗ. Now ΙΗ was a familiar contraction of the sacred name of Jesus, and is so written in the Alexandrian papyri of the period; and the letter Τ looked like the cross." The same gematria was adopted by Clement of Alexandria and by several other Church Fathers: William Barclay notes that, because the letter T is shaped exactly like the "crux commissa" and because the Greek letter T represented the number 300, "wherever the fathers came across the number 300 in the Old Testament they took it to be a mystical prefiguring of the cross of Christ".