Michal took an image - התרפים את eth hatteraphim, the teraphim. The Hebrew word appears to mean any kind of image, in any kind of form, as a representative of some reality. Here it must have been something in the human form; because it was intended to represent a man lying in bed indisposed.
A pillow of goats' hair - Perhaps she formed the appearance of a sick man's head muffled up by this pillow or bag of goats' hair. So I think the original might be understood. The goats' hair was merely accidental; unless we could suppose that it was designed to represent the hair of David's head, which is not improbable.
An image - “Teraphim” (see the margin), an image, or bust in human form, and as large as life, of a kind of household god, to the worship of which the Israelites, and especially women, were much addicted.
A pillow - It was probably a quilt or blanket of goats‘ hair and of common use as a bed-covering. Whether Michal drew it over the head of the teraphim, as if for warmth, and so covered it, or whether she disposed it about the head so as to look like hair, is not clear.