Jamieson, Fausset and Brown on 1 Samuel 19:13-14

13-14. And Michal took an image, and laid it in the bed--"an image," literally, "the teraphim," and laid, not in the bed, but literally on the "divan"; and "the pillows," that is, the cushion, which usually lay at the back of the divan and was stuffed with "goat's hair," she took from its bolster or heading at the upper part of the divan. This she placed lower down, and covered with a mantle, as if to foster a proper warmth in a patient; at the same time spreading the goat's hair skin, so as to resemble human hair in a dishevelled state. The pretext was that David lay there sick. The first messengers of Saul, keeping at a respectable distance, were deceived; but the imposition was detected on a closer inspection.