John Gill Commentary 2 Samuel 15:14

"And David said unto all his servants that were with him at Jerusalem, Arise, and let us flee; for else none of us shall escape from Absalom: make speed to depart, lest he overtake us quickly, and bring down evil upon us, and smite the city with the edge of the sword." — 2 Samuel 15:14 (ASV)

And David said unto all his servants that [were] with him at
Jerusalem
His courtiers and ministers of state, the officers of his household, as many of them as were with him in the city; for some of them very probably were in the country, as Ahithophel was, and some might be along with Absalom, whom he had invited to his peace offerings:

arise, and let us flee ;
it is much that a man of such courage and valour as David should be so intimidated at once as to make a flight as soon as he heard of a conspiracy forming against him:

for we shall not [else] escape from Absalom ;
his fears ran so high, that he fancied he would be upon them presently:

make speed to depart, lest he overtake us suddenly ;
which still more clearly shows the panic he was in:

and bring evil upon us ;
kill them, or make them prisoners:

and smite the city with the edge of the sword ;
the inhabitants of it, should they make resistance.