Bede

But Michal took an image and laid it on the bed, etc. The history of the hairy skin, of the skins of goats, is evident; for there was a cushion sewn of goat's skin, which, with its unshorn hairs, feigned the head of a man lying in bed. The statue, however, is an imitation of the true and living; the dead skin of goats is the remains of a dead animal. Therefore, Michal took an image and placed it on David's bed, as he was let down through the window and secretly saved. …

Commentary on Samuel ↗