Charles Ellicott Commentary 2 Samuel 20:12

"And Amasa lay wallowing in his blood in the midst of the highway. And when the man saw that all the people stood still, he carried Amasa out of the highway into the field, and cast a garment over him, when he saw that every one that came by him stood still." — 2 Samuel 20:12 (ASV)

The people stood still. —These were probably the very people whom Amasa had just been gathering from Judah and Benjamin. Whoever they may have been, they were naturally overcome and paralysed for the moment at the sight of the great leader whom the king had just promoted wallowing in his blood. Joab’s warrior, seeing the effect of their consternation, removed and concealed the body, and the pursuit then went on.