The desire to restore David to power is not universal. While many of the people are calling for it, there is a reluctance on the part of those in the nation's leadership to call David back to Jerusalem (verses 10-12). Perhaps they fear David will take revenge on Absalom's supporters. So David orders the priests to begin encouraging the elders to support his return—which they do. And David returns to his capital.
In the meantime, David assigns his nephew Amasa (Joab's cousin) the job of commander over the army in place of Joab. By appointing the man who had been commander of Absalom's army to head the combined forces, he secures the allegiance of those who followed Absalom. Furthermore, Amasa also has influence among the leaders of Judah. All of this is helpful in uniting the kingdom. At the same time, Joab is, in some measure, punished for all the crimes he has committed, including the recent one of disobeying David's direct orders about not harming Absalom.
Upon coming back to Jerusalem, David demonstrates great restraint in his clemency to Shimei, binding himself with an oath not to harm the man. He apparently still sees Shimei's actions as somewhat justified. And he wants the civil war to be completely over with no more bloodshed. However, on later reflection, David will apparently come to see this whole situation differently. He originally looked upon Shimei's cursing as ordered by God (2 Samuel 16:11). However, Shimei's cursing was over David usurping Saul's throne—a complete falsehood—rather than over David's real sins. At some point, he will decide that Shimei should be executed for his crime of cursing the king, yet David won't be able to do this because of his oath. Therefore, he will order his son Solomon to deal with Shimei (1 Kings 2:8-9, 1 Kings 2:36-46).
David also restores Mephibosheth after he explains his position on what happened earlier. We read a different version given by his servant Ziba in 2 Samuel 16:1-4. There is quite a contrast in the two stories. Mephibosheth's story makes sense and yet Ziba really did put himself in mortal danger from Absalom. Not knowing who is telling the truth, the king requires that the two men divide the wealth equally between themselves. After all, what else can he do at this point?
We are told in the Scriptures that one should not decide a matter before hearing both sides—that the first one to present his case often seems correct until the person on the other side has his say (Proverbs 18:13, Proverbs 18:17). David had not originally followed these principles in this situation.
Concerning 2 Samuel 19:37-38, Chimham is evidently Barzillai's son (see 1 Kings 2:7). Barzillai declines to accept David's offer for himself, but suggests that Chimham be the recipient of David's gratitude in his stead—to which David readily agrees.
Next we see the growing rivalry and resentment between Judah and the northern 10 tribes of Israel. The following chapter will show how a certain Sheba takes advantage of the widespread instability, suspicion and bitterness to lead Israel in a revolt against David and Judah (2 Samuel 19:40-43).