Kitto's Popular Cyclopedia of Biblial Literature
A´chish (called Abimelech in the title of Psalms 34), the Philistine king of Gath, with whom David twice sought refuge when he fled from Saul (1 Samuel 21:10-15; 1 Samuel 27:1-3). The first time David was in imminent danger; for he was recognized and spoken of by the officers of the court as one whose glory had been won at the cost of the Philistines. This talk filled David with such alarm that he feigned himself mad when introduced to the notice of Achish, who, seeing him 'scrabbling upon the doors of the gate, and letting his spittle fall down upon his beard,' rebuked his people sharply for bringing him to his presence, asking, 'Have I need of madmen, that ye have brought this fellow to play the madman in my presence? Shall this fellow come into my house?' After this David lost no time in quitting the territories of Gath. About four years after, when the character and position of David became better known, and when he was at the head of not less than 600 resolute adherents, he again repaired with his troop to King Achish, who received him in a truly royal spirit, and treated him with a generous confidence, of which David took perhaps rather more advantage than was creditable to him [DAVID].
Kitto, John, ed. Entry for 'Achish'. "Kitto's Popular Cyclopedia of Biblial Literature". https://www.studylight.org/encyclopedias/eng/kbe/a/achish.html.