Exodus 25:10. Two cubits and a half shall be the length thereof, and a cubit and a half the breadth thereof, and a cubit and a half the height thereof.
The word cubit is derived directly from the Latin cubitus, the lower arm. The Hebrew word is ammah, the mother of the arm, that is, the forearm. It is evidently a measure taken from the human body; as were other measures of length among the Hebrews and other nations. There seem to be two kinds of cubits, and some say three kinds, mentioned in Scripture. In Deuteronomy 3:11, we read of “the cubit of a man.” In 2 Chronicles 3:3, “cubits after the first [or old] measure” are spoken of. In Ezekiel 41:8, we are told of “great cubits,” each one of which, according to Ezekiel 40:5, “measured a cubit and a handbreadth.” Some writers suppose these to represent three different measures of length; while others regard the first and second as identical, thus making but two kinds of cubits. Whether two or three cannot now be determined. It is no easier to decide as to the length of any one of the cubits named. Various estimates of the Mosaic cubit have been given, varying from twelve inches to twenty-two. The ancient Egyptian cubit was nearly twenty-one inches, which some of the best authorities now estimate as the length of the Mosaic. Other authorities, however, equally worthy of consideration, claim that the length of the Mosaic cubit, as applied to the Tabernacle and Temple, was eighteen inches; and that the Jews did not use the cubit of twenty-one inches—which was Babylonian as well as Egyptian—until after the captivity.