(4) To Amasa.--Thus David begins the fulfilment of his promise of 2Samuel 19:13. It proved an act of very doubtful expediency at this crisis.

Verse 4. - Then said the king to Amasa. David thus takes the first step towards depriving Joab of the command (see 2 Samuel 19:13). This was a most unwise step, however guilty Joab may have been in slaying Absalom. With all his faults, Joab had always been faithful to David, and it was chiefly his skill in war and statesmanlike qualities which had raised the kingdom to a position of great power. Just now, too, he had crushed with smaller forces a rebellion in which Amasa had taken the lead. To cast him off and put Amasa in his place might please conspirators, and reconcile them to their defeat, but it would certainly offend all those who had been faithful to David in his troubles. Throughout David acts as one whose affections were stronger than his sense of duty, and his conduct goes far to justify Joab's complaint, "This day I perceive, that if Absalom had lived, and all we had died this day, then it had pleased thee well" (2 Samuel 19:6). If David, in the administration of his kingdom, acted with as little forethought as in the slight he cast-upon the ten tribes in negotiating with Judah to be the first to restore him, as it had been the first tribe to rebel, instead of waiting for the rest, and doing his best to make the day of his return one of general concord and good will; or with as little justice as in the matter of Ziba and Mephibosheth; or with as little tact and good sense as in substituting at the end of a revolt the rebel general for the brave soldier who had "saved his life, and the lives of his sons and of his daughters, and the lives of his wives and of his concubines" (2 Samuel 19:5); we cannot wonder that he had failed to secure the allegiance of a race so self-willed and stubborn as the Israelites. One cannot help half suspecting that Joab had used the power he had gained over the king by the part he had taken in the murder of Uriah tyrannically, and for cruel purposes, and that David groaned under the burden. But if so, it was his own sin that was finding him out.

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.Then said the king to Amasa,.... Whom he had promised to make general of his army, 2 Samuel 19:13; and by the following order declared him such:

assemble me the men of Judah within three days; which was done by the sound of the trumpet, or by the proclamation of a herald; it seems that the men of Judah, who attended David to Jerusalem, were gone to their respective cities and places of abode, or there would have been no occasion for such a summons; though it is strange they should, when the men of Israel appeared so inclinable to a new rebellion:

and be thou here present; to take the command of them.