The account with Ammon had by no means been settled, and in the Spring David sent Joab and the armies of Israel to battle the Ammonites and to besiege their capital city, of Rabbah. We are told specifically that this was the time when kings go out to battle, but David remained at home. lt is possible his servants advised this so that their king would not be exposed to danger (ch.18:3), but David's energy of faith had waned so that he was exposed to greater danger by remaining at home.
Evident idleness led to his shameful fall, for he rose from his bed in the evening while it was still light enough for him to see from his rooftop a woman bathing herself (v.2). Honest self-judgment should have turned his eyes and his thoughts away immediately, but he was allured by her beauty. Inquiring about her, he found she was another man's wife. Why did this fact not stop him? He already had seven wives. He knew the law of God, that an adulterer should be put to death (Deuteronomy 22:23-24), but took advantage of his own position as king to break over the law of God. The woman's husband, Uriah, was a soldier in Joab's army, therefore away from home, and David sent messengers to bring her to him. After their shameful guilt of adultery, she returned to her own home (v.4).
David may have hoped that this was the end of the matter, but God intervened in His righteous government. Bathsheba sent word to David that she had become pregnant (v.5). Alarmed at this, David conceived a subtle plan to keep his sin from being discovered. He sent orders to Joab to send Uriah back to Jerusalem. Uriah may have wondered what reason David had for bringing him back, for David only inquired how the battle was going, then told Uriah to go to his house and wash his feet, for a soldier's feet need special care. When Uriah left, David sent a present after him (v.8). Whether Uriah received it did not go there, but stayed overnight with others of David's servants in the servants' quarters.
On hearing this, David questioned Uriah as to why he did not go to his house when he had opportunity after some time of being away from home (v.10). Uriah's reply must have been a pointed lesson to David as to self restraint. He had decided that, since the ark and Israel were in temporary shelters, and that Joab and the army were camping in the open, engaged in serious combat for the sake of Israel, he was not going to relax and enjoy himself at home as though he was not a part of Israel defense: he would virtually remain "on guard."
When David failed to get Uriah to go to his home the first night, then he tried another tactic, telling Uriah to stay in Jerusalem for two more days, but having him eat and drink with him till Uriah became drunk, David thinking in this way to tempt Uriah to go to his home. But this plan failed too: Uriah again slept with the servants.
David's desperation then gave birth to the awful thought of plotting to have Uriah killed. Uriah was given a letter to carry to Joab that was intended to seal his own doom. This was the reward of his devotedness to the cause of Israel! David did not even try to veil his intentions concerning Uriah: he told Joab to place him in the front line of the fiercest battle, then have all others withdraw, so that Uriah would be left as the only target for the enemy, and thus be killed (v.15). Not only would David make himself guilty of the murder of Uriah, but he would implicate Joab and others in this too. Joab of course would say he had to obey his master, but in this case he ought to have had a conscience toward God that would not allow him to obey David.
However, in besieging the city, Joab put Uriah in the greatest place of danger, evidently close to the wall. Men from the city saw an advantage in coming Out to fight, having the protection of the city behind them, and Joab's plan worked well, not for the good of Israel, but to have Uriah killed. Others also fell before the enemy, but Joab knew this was a risk he must take in order to be sure that Uriah was killed (v.17).
Joab may not have been so quick to report to David the conduct of the war if it had not been for Uriah's death. When he sends a messenger, he instructs him to tell first the events that transpired, and wait for a response from David before saying any more (v.19). Then if David was angry because of Joab's endangering his army by coming too close to the wall (a tactic Joab, as well as David, knew was dangerous), the messenger was to add that Uriah the Hittite was dead also (v.21). Joab intended to impress on David the fact that he had planned this unwise ploy because David wanted Uriah killed.
However, the messenger did not follow Joab's orders precisely. He reported what had happened in the battle, that men had come out from the city and Israel pressed them close to the gate, with the result that archers could shoot from the wall, and some of David's men were killed. But he did not wait for a response from David before telling him that Uriah was among the dead (v.24). Perhaps he saw no reason for Joab's instructions and did not want to see David's anger rise.
Of course the only news that interested David at the moment was that of Uriah's death. Likely the messenger wondered why David did not criticize Joab's action in the battle, but David only mildly told the messenger to tell Joab not to be discouraged by this setback, because "the sword devours one as well as another" (v.25). In this way he tried to disguise the relief he felt at news of Uriah's death, but this would be plainly apparent to Joab. David only added that Joab should increase the intensity of the battle so as to overthrow the city.
Of course Bathsheba did not know that David had planned her husband's death. She did mourn for her husband for a certain time (v.26). When the days of mourning were over, David sent for her and took her as his eighth wife, and she bore a son. But we are assured that what David had done was evil in the sight of the Lord. This could not go unpunished.