Leviticus 6:9

9.Command Aaron and his sons. He more distinctly explains what might have appeared to be omitted; nor is it without reason that he carefully enters into these full details, for since God prefers obedience to all sacrifices, he was unwilling that anything should remain doubtful as to the external rites, which were not otherwise of great importance; that they might learn to observe precisely, and with the most exact care, whatever the Law commanded, and that they should not obtrude anything of themselves, inasmuch as the purity of the holy things was corrupted by the very smallest invention. He would, therefore, leave nothing to the people’s judgment, but directed them by a fixed rule even in the most trifling matters. As to the burnt-offerings, he commands that they should not be taken away from the altar till they were consumed by the fire; but after they were put on, he commands them to be burnt in a constant fire till the morrow. With this intent, he expressly says, that the fire should be kept alight on the altar all the night, since the sacrifices would not have been reduced to ashes without the application of fuel. Secondly, he commands the priest, clothed in the linen garment, and breeches, as he was wont to be in the performance of his sacred duties, to go to the altar, and to take away the ashes and put them by the side, or at some part of the altar; but when he shall have gone away from the altar, he bids him take off his holy garments, and carry the ashes out of the camp to a clean place. But what he had before briefly adverted to as to the supply of wood, he immediately declares more fully to be, lest the fire should go out. Again, he assigns to the priest the office of setting the wood in order every morning. But, because in the sacrifices (275) of prosperities the Law commanded the fat only to be burnt, Moses now adds, verse 12, that the fat was to be burnt on the same fire. It is worthy of particular observation, that he finally subjoins a precept as to so keeping up the fire that it may never go out.

The intent of this perpetuity was, that the offerings should be burnt with heavenly fire; for on the day that Aaron was consecrated, the sacrifice was reduced to ashes not by human means but miraculously, in token of approbation. True that God did not choose daily to exert this power; but He interposed the hand and labor of men in such a manner that the origin of the sacred fire should still be from heaven. The same thing afterwards happened at the dedication of Solomon’s temple, because that alteration of the divine decree demanded a sign (tesseram,) lest any should think that it was at the will of man that the splendor of the temple should outvie the tabernacle. Finally, the sacrifice of Elijah was graced by the same privilege when he restored the abolished legal service; and then also God upheld what He had ordained in His Law, in opposition to all corrupt and degenerate rites. Meanwhile, in order to prevent any adulterations, He chose to have the fire continually burning on the altar day and night, nor was it allowable to take it from elsewhere. There was, indeed, amongst the Persians (276) a perpetual fire, and at Rome also under the guardianship of the Vestal virgins; (277) and it may be, that in foolish mimicry they transferred to themselves the custom which they had heard of being observed by the Jews; for thus it is that, for the purpose of deceiving unbelievers, the devil often falsely makes a pretense of something divine, and imitates God just as an ape imitates man: but the purpose of God in rejecting strange fire was to retain the people in His own genuine ordinance prescribed by the Law, lest any inventions of men should insinuate themselves; for the prohibition of strange fire was tantamount to forbidding men to introduce anything of their own, or to add to the pure doctrine of the Law, or to decline from its rule. Meanwhile, since God had once testified, as if by stretching forth His hand from heaven (to receive them, (278)) that the sacrifices were acceptable to Him, believers were confirmed in their confidence of this by the pledge of the perpetual fire.