Ezekiel 9:4

4. Set a mark upon the foreheads Literally, set a tau ( T) upon the foreheads. Tau was the last letter of the Hebrew alphabet, which in ancient times had the form of a cross. The cross is one of the simplest and therefore one of the most common “marks” used by ancient peoples. (See Job 31:35, Hebrews) Perhaps this is the only reason why it is commanded to be used here; yet it is a suggestive fact that centuries before Ezekiel’s time the cross had been used as a sacred symbol. The kings and nobles of Egypt covered themselves with long chains of interwoven crosses and held this “symbol of life” ( † ) in their dying hands as reverently as any Roman Christian ever cherished his crucifix. Among the Babylonians this same symbol is found. The Hebrews must have known of the symbolic value attached to the cross, and it is just like Ezekiel to express in this striking way the fact that the gift of life had come from God upon all those marked with the mysterious letter which, it may be noticed, was also the initial of the Hebrew word “live.” (Compare Revelation 7:3; Revelation 22:4.) This seal of grace was to be put upon all men, women, and children (Ezekiel 9:5-6) who sorrowed over their city’s sin. The cross on the forehead corresponds exactly to the blood upon the doorposts when the destroying angel flew over Egypt. (Compare Galatians 6:17.) Both marks the blood and the cross were chosen, not arbitrarily, but because they were “inwardly connected” with the facts indicated (Keil). Neither Moses nor Ezekiel could have known, but Infinite Wisdom foresaw, the peculiar significance and correspondence of these strange symbols. The man with the inkhorn was not to put any mark upon the foreheads of the people but this. It was the sign of the cross that saved them. “This mark was, of course, only visible to the angels.” Orelli.