Exodus 25:3

“And this is the offering which ye shall take of them, etc.] That is, some one or other of the following things were to be taken of each of them that had a heart, and it was in the power of their hands to give; it was not expected that something of each of these should be had of everyone, but every man was to give, and it was to be received of him, what of these would suit him best to bestow, some one thing, some another, as they were possessed of, and had a heart to give; and for which service many of them were abundantly supplied with what they had brought out of Egypt; and as it was the Lord that gave them favour in the eyes of the Egyptians to lend or give them the riches they had, they…”

“this is the offering which ye shall take of them--the articles of which the offerings should consist. brass--rather copper, brass being a composite metal.”

“Yahweh had redeemed the Israelites from bondage. He had made a covenant with them and had given them laws. He had promised, on condition of their obedience, to accept them as His own “peculiar treasure,” as “a kingdom of priests and an holy nation” Exodus 19:5-6. And now He was ready visibly to testify that He made his abode with them. He claimed to have a dwelling for Himself, which was to be in external form a tent of goats’ hair Exodus 19:4, to take its place among their own tents, and formed out of the same material (see Exodus 26:7 note). The special mark of His presence within the tent was to be the ark or chest containing the Ten Commandments on two tables of stone Exodus 31:18,…”

“brass: Nechosheth, rather, copper; as brass is a factitious metal, composed of copper, and the oxide or ore of zinc, called lapis calaminaris. Deu 8:9; Job 28:2 Exodus 25:4”