2 Samuel 20:8

When they were at the great stone which is in Gibeon, Amasa went before them. And Joab's garment that he had put on was girded unto him, and upon it a girdle with a sword fastened upon his loins in the sheath thereof; and as he went forth it fell out.

Amasa went before them. Having collected some forces, he by a rapid march overtook the expedition at Gibson, and assumed the place of commander, in which capacity he was saluted, among others, by Joab.

Joab's garment ... was girded - in the fashion of travelers and soldiers.

A girdle with a sword fastened upon his loins, х maatªnaayw (H4975) = his side (cf. Ezekiel 9:2)]. This statement receives ample illustration from the Assyrian sculptures, on which warriors are depicted, their swords not on their thigh, but on the loin or side.

A sword ... and as he went forth it fell out - i:e., out of the scabbard. The sword or dagger was fixed into the girdle in a horizontal direction, not suspended from it. In this position Joab's sword falling out of the large sheath might appear an accident very likely to happen; whereas it could not possibly have fallen out had it hung loosely and perpendicularly, like the swords of the moderns. 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 honour and homage.