Bolster

Bolster is the King James Version rendering of the Hebrew kebir in 1 Samuel 19:13, 16, where Michal placed a household idol (teraphim) in David's bed with a bolster of goat's hair at its head to deceive Saul's messengers into thinking David was still abed. The word describes a cylindrical pillow or head-covering. In 1 Samuel 26, the “bolster” (more precisely, the area “at his head”) of Saul's sleeping form marks the location of his spear and water jug, which David took as proof that he had been within reach of the king yet spared his life.

The item in 1 Samuel 19 is more accurately translated “a quilt of goat's hair” (so the Revised Version marginal reading), used to simulate the head of a sleeping man. The episode is one of several in the David narratives where disguise and deception serve providential ends, and Michal's stratagem allowed David to escape what would have been his death had Saul's servants arrived earlier.