Jamieson, Fausset and Brown on 1 Samuel 25:23

23. she hasted, and lighted off the ass, and fell before David on her face--Dismounting in presence of a superior is the highest token of respect that can be given; and it is still an essential act of homage to the great. Accompanying this act of courtesy with the lowest form of prostration, she not only by her attitude, but her language, made the fullest amends for the disrespect shown by her husband, as well as paid the fullest tribute of respect to the character and claims of David.