There is an ancient marble inscription mounted on the south wall of the Chapel of the Forty Martyrs of Sinai and Raithou.
+ Τῆς δ΄ δεκάδος τὴν διὰ τοῦ αἵματος κολυμβήθραν ζηλώσαντες οἱ ἰσάριθμοι ὅσιοι π(ατέ)ρ(ε)ς / ἐνθάδε κατάκεινται, ὧν ἡ εὐφροσύνη ἡ βάτος ἡ ἀληθινὴ ὑπάρχει· δι᾿ ὧν ὁ θ(εὸ)ς σῶσον ἡμᾶς +
+ Having emulated the baptism by blood of the 4 ten, the righteous fathers equal-in-number / lie in this place. Theirs is the joyous and true Burning Bush. Through them, O God, save us +
Scholars have had different opinions about the best way to understand and translate δ΄ δεκάδος. The simplest explanation is that it refers to the ‘four [ranks of] ten’ who were martyred at Raithou, with an equal number at Sinai.
The Burning Bush is an emblem for being in the very presence of God.