Thou shalt put it under the compass. The "compass" (karkob) is spoken of as if it were something well-known; yet it had not been previously mentioned. Etymologically the word should mean "a cincture" or "band" round the altar; and thus far critics are generally agreed. But its position, size, and object, are greatly disputed. Some hold that it was a broad bench, or step, on which the officiating priests stood at the time of a sacrifice, and that its position was about the middle of the altar. Others think that it was a mere border round the top, from which the net-work depended, and that the object of both was to catch anything that might fall from the altar. Others again, while placing it mid-way in the altar, regard it as a mere ornament, only projecting slightly, and forming a sort of finish to the net-work. This, which is the view of Knobel, seems to be, on the whole, the most probable one. That the net may be even to the midst of the altar. If the" compass" was at the top, the net must have extended thence to the middle. If it was mid-way in the altar, the net must have covered the lower half. To us this latter seems the more probable view. But the point is uncertain.
Staves, or polos, were needed for the carriage of the altar from place to place, as for the ark (Exodus 25:13) and the table of shew-bread (Exodus 25:28). They were to be inserted into the rings mentioned in Exodus 27:4. As the altar was of bronze, so the rings were to be of bronze, and the staves overlaid with bronze. There is a gradual descent in the preciousness of the materials from the holy of holies to the holy place, and from that to the court.