Seven hundred men - These were no doubt the choice of all his troops, and being afraid of being hemmed up and perhaps taken by his enemies, whom he found on the eve of gaining possession of the city, he made a desperate sortie in order to regain the open country; and supposing that the quarter of the Edomites was weakest, or less carefully guarded, he endeavored to make his impression there; but they were so warmly received by the king of Edom that they failed in the attempt, and were driven back into the city. Hence he was led to that desperate act mentioned in the following verse.
To break through, even unto the king of Edom - Either because he thought that the king of Edom would connive at his escape or to take vengeance on him for having deserted his former allies (2 Kings 3:8 note).