Ezekiel 1:22

And the likeness of the firmament Rather: and there was a likeness over the heads of the living creature (of) a firmament. The term "firmament" has come from the LXX. (stereôma) through the Vulgate. The verb is used of the creation of the earth, Isaiah 42:5; Isaiah 44:24; Psalms 136:6, and once, Job 37:18, of the creation of the heavens; and the noun is always used of the heavens. In the above passages LXX. renders "make strong," and the noun "firmament." The word "firmament" occurs only in Genesis 1; Ezekiel 1; Ezekiel 10:1; Psalms 19:1; Psalms 150:1; Daniel 12:3.

the terrible crystal Cf. Exodus 24:10, "and they saw the God of Israel, and there was under his feet as it were a pavework of sapphire stone, and as it were the very heaven for clearness." In Revelation 4, which is largely indebted to Ezekiel 1, the crystal firmament here becomes "a sea of glass like unto crystal" (Ezekiel 1:6). The word "terrible" is wanting in LXX., which reads also asa firmament in the first clause.