Hermas (4.2.6-4.3.4)

Believe on the Lord, you who are double-minded, that he can do all things, and turns his wrath away from you, and sends scourges on you who are double-minded. Woe to those who hear these words and disobey; it were better for them not to have been born.

I asked her concerning the four colours which[*] the beast had on its head. She answered and said to me, Are you again curious about such matters? Yes, I said, Lady, let me know what they are.

Listen, she said, the black is this world, in which you are living;

the colour of fire and blood means that this world must be destroyed by blood and fire.

The golden part is you, who have fled from this world, for even as gold is tried in the fire, and becomes valuable, so also you who live among them,[*] are being tried. Those then who remain and pass through the flames shall be purified by them. Even as the gold puts away its dross, so also you will put away all sorrow and tribulation, and will be made pure and become useful for the building of the tower.