Ambrose of Milan

By the heaven then being brass is signified its being shut up, and refusing its use to the earth. The earth also is iron, for it witholds its produce, and with hostile rigour excludes from its fructifying soil the seeds thrown upon it, which its wont is to cherish as in the bosom of a tender mother. For when does iron bring forth fruit, when does brass melt into showers?

Letters 61-70 ↗