Numbers 31:30

³⁰ `And from the sons of Israel's half thou dost take one possession out of fifty, of man, of the herd, of the asses, and of the flock, of all the cattle, and thou hast given them to the Levites keeping the charge of the tabernacle of Jehovah.'

Brass

Brass and iron as in Isaiah 48:4 and Daniel 7:19 signify what is hard.

In Genesis 4:22, brass signifies natural good. (Arcana Coelestia 421)

In Numbers 21:9, this signifies the Lord's divine natural. (Apocalypse Revealed 49)

Brass also signifies the good in man's natural and the sensuous in the Lord. (Arcana Coelestia 197, Apocalypse Revealed 49, Apocalypse Explained 705)