As soon as Amasa’s body was removed from the road, all the men went on with Joab to pursue Sheba son of Bichri.
We have here Amasa's fall just as he began to rise. He was nephew to David (Sa2 17:25), had been Absalom's general and commander-in-chief of his rebellious army, but, that being routed, he came over into David's interest, upon a promise that he should be general of his forces instead of Joab.
Commenting on 2 Samuel 20:4-13
When he was removed out of the highway,.... Into the field, and covered over with a cloth, that he could not be seen: all the people went on after Joab; made no stop at all, knowing nothing of the matter, or what had happened: to pursue after Sheba the son of Bichri; these were the troops that Amasa had been assembling, which followed one another...
2Sa 20:12-13 Amasa lay wallowing in blood in the midst of the road; and when the man (the attendant) saw that all the people stood still (by the corpse), he turned (pushed) Amasa from the road to the field, and threw a cloth over him, whereupon they all passed by and went after Joab.
Commenting on 2 Samuel 20:12-13