1 Samuel 21:13

He changed his behaviour. The same word is used in the title of Psalms 34:1-22 . Literally it means "his taste," and, like the Latin word sapientia, is derived from the action of the palate, and so from the faculty of discriminating flavours it came to signify the power of discrimination generally. Thus "to change his taste" means to act as if he had lost the power of distinguishing between objects. Feigned himself mad. Literally, "he roamed hither and thither" restlessly and in terror. In their hands. I.e. before them, in their presence. Scrabbled on the doors of the gate. The Vulgate and Septuagint read drummed upon them. Literally the verb means "to make the mark of a Tau," the last letter of the Hebrew alphabet, and which anciently was in the form of a cross. The gate, on the leaves of which David scrawled, was probably that of the court or waiting room, in which the servants of Achish passed their time when in attendance upon him. Possibly David had witnessed these symptoms of madness in Saul's case during his fits of insanity. The idea of some of the older commentators, that David really for a time went out of his mind, is opposed to the general sense of the narrative.