'Thirty' has a twofold significance because it is is the product of five and six, and also three and ten. From five multiplied by six, it signifies some aspect of combat, because 'five' signifies some part or aspect, and 'six,' combat. From three multiplied by ten, it signifies something full of remains of good and truth, because 'three' signifies fullness, and 'ten,' remains of good and truth. A composite number involves the same as the simple numbers it has as its factors.

(Odkazy: 2 Samuel 5:4; Arcana Coelestia 5335; Luke 3, 3:23, 23; Numbers 4:3, 4:23, 4:30)

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)

(Odkazy: Apocalypse Explained 70)