As God intended in the tabernacle to manifest his presence among his people, so there they were to pay their devotions to him, not in the tabernacle itself (into that only the priests entered as God's domestic servants), but in the court before the tabernacle, where, as common subjects, they attended. There an altar was ordered to be set up, to which they must bring their sacrifices, and on which their priests must offer them to God: and this altar was to sanctify their gifts. Here they were to present their services to God, as from the mercy-seat he gave his oracles to them; and thus a communion was settled between God and Israel. Moses is here directed about, 1. The dimensions of it; it was square, Exo 27:1. 2. The horns of it (Exo 27:2), which were for ornament and for use; the sacrifices were bound with cords to the horns of the altar, and to them malefactors fled for refuge. 3. The materials; it was of wood overlaid with brass, Exo 27:1, Exo 27:2. 4. The appurtenances of it (Exo 27:3), which were all of brass. 5. The grate, which was let into the hollow of the altar, about the middle of it, in which the fire was kept, and the sacrifice burnt; it was made of network like a sieve, and hung hollow, that the fire might burn the better, and that the ashes might fall through into the hollow of the altar, Exo 27:4, Exo 27:5. 6. The staves with which it must be carried, Exo 27:6, Exo 27:7. And, lastly, he is referred to the pattern shown him, Exo 27:8.

Now this brazen altar was a type of Christ dying to make atonement for our sins: the wood would have been consumed by the fire from heaven if it had not been secured by the brass; nor could the human nature of Christ have borne the wrath of God if it had not been supported by a divine power. Christ sanctified himself for his church, as their altar (Joh 17:19), and by his mediation sanctifies the daily services of his people, who have also a right to eat of this altar (Heb 13:10), for they serve at it as spiritual priests. To the horns of this altar poor sinners fly for refuge when justice pursues them, and they are safe in virtue of the sacrifice there offered.

Thou shalt make for it a grate - Calmet supposes this altar to have been a sort of box, covered with brass plates, on the top of which was a grating to supply the fire with air, and permit the ashes to fall through into the siroth or pan that was placed below. At the four corners of the grating were four rings and four chains, by which it was attached to the four horns; and at the sides were rings for the poles of shittim wood with which it was carried. Even on this there is a great variety of opinions.

And thou shalt, make for it a grate of network of brass,.... Or "sieve", as in Amo 9:9, it was a plate of brass with holes in it, to let through either the blood that drained from the parts of the sacrifice, or the ashes of it; for this was the focus or hearth, on which the sacrifice and the wood were laid and burnt: this, according to the Targum of Jonathan on Exo 38:4 was to receive the coals and bones which fell from the altar: and so may denote the purity of Christ's sacrifice, which was offered up without spot to God, and the use of him as the altar to sanctify our gifts, and take away the sins of our holy things:

and upon the net shalt thou make four brazen rings in the four corners thereof; by which, with chains put into them, the grate was fastened to the four horns of the altar, and the use of them was to let it down and hang in the middle of the altar, and to take it up when there was occasion for it; though some think these rings were not "in" the grate, but "by" it, as the particle may be rendered, a little lower than that, on the sides of the altar; into which the staves after mentioned were put, and with which the altar was carried when removed from place to place.

a grate of network of brass--sunk latticework to support the fire.

four brazen rings--by which the grating might be lifted and taken away as occasion required from the body of the altar.