What was the brazen altar made of?
The brazen altar was made of acacia wood, the desert wood, and covered with brass rather than gold. This is why it is called the brazen altar. Throughout Scripture brass denotes judgment, and the altar where sacrifices were committed was wood covered with brass.
Les explains that the brazen altar was constructed of acacia wood, the desert wood, and covered with brass, not gold. He notes that brass throughout Scripture speaks of judgment. For example, the brazen serpent Moses erected judged Israel's sin when they looked at it, and the cross was where sin was judged. Therefore, the altar where sacrifices were committed was wood covered with brass, called the brazen altar.