Jamieson, Fausset & Brown

the spear that is at his bolster, and the cruse of water--The Oriental spear had, and still has, a spike at the lower extremity, intended for the purpose of sticking the spear into the ground when the warrior is at rest. This common custom of Arab sheiks was also the practice of the Hebrew chiefs. at his bolster--literally, "at his head"; perhaps, Saul as a sovereign had the distinguished luxury of a bolster carried for him. A "cruse of water" is usually, in warm climates, kept near a person's couch, as a drink in the night time is found very refreshing. Saul's cruse would probably be of superior materials, or more richly ornamented than common ones, and therefore by its size or form be easily distinguished.