Charles Ellicott Commentary Exodus 27:4

"And thou shalt make for it a grating of network of brass: and upon the net shalt thou make four brazen rings in the four corners thereof." — Exodus 27:4 (ASV)

A grate of network. —Rather, a grating of network. The position of the grating is doubtful. According to one view, it reached from the middle of the altar to its base, and protected the sides of the altar from the feet of the ministering priests. According to another, it surrounded the upper part of the altar, and was intended to catch any portions of the victims that accidentally fell off. There are no sufficient data to enable us to determine between these views.

Upon the net shalt thou make four brasen rings. —The brazen altar, like the ark and the table of the bread of the Presence, was to be carried by the priests when the Israelites changed their camping-ground. It therefore required “rings,” like them (Exodus 25:12; Exodus 25:26). These were, in the case of the altar, to be attached to the network, which must have been of a very solid and substantial character.