Commentaries
20:4-13 Joab barbarously murdered Amasa. The more plot there is in a sin, the worse it is. Joab contentedly sacrificed the interest both of the king and the kingdom to his personal revenge. But one would wonder with what face a murderer could pursue a traitor; and how, under such a load of guilt, he had courage to enter upon danger: his conscience was seared.
8. Amasa went before them—Having collected some forces, he by a rapid march overtook the expedition at Gibeon, and assumed the place of commander; in which capacity, he was saluted, among others, by Joab.
Joab's garment, that he had put on was girded unto him—in the fashion of travellers and soldiers.
a sword … and as he went forth it fell out—that is, out of the scabbard. According to Josephus, he let it drop on purpose as he was accosting Amasa, that stooping, as it were accidentally, to pick it up, he might salute the new general with the naked sword in his hand, without exciting any suspicion of his design.
He went forth—in a ceremonious manner to meet Amasa, now commander-in-chief, in order to seem to render to that officer, whom he considered as usurping his post, a conspicuous honor and homage.