Gregory the Dialogist

They are wet with the showers of the mountains, and embrace the stones for want of a garment. 'The showers of the mountains' are the words of the learned. Of which same 'mountains' it is delivered by the voice of Holy Church; I lifted up mine eyes unto the hills: and so those persons, 'the showers of the mountains wet,' in that the streams of the holy fathers fill them to the full. …

Morals on the Book of Job, Book XVI ↗

Thomas Aquinas

Clothes are not only necessary to keep warm against the cold, but also as a protection against the rain. Thus those left naked by thieves must not only be afflicted by the cold, but also get soaked by the rain. He expresses this saying, "they are soaked by the rain of the mountains." Men often flee to mountainous places which are more fortified from the fear of other thieves or enemies. There the rains are more frequent and severe because of the cold character of the climate, and naked men especially suffer. …

Commentary on Job ↗