Chapter 19

Joab pretty severely rebukes David for his loud public mourning.  Joab tells him that those who fought for the king that day saved the lives of all the rest of David's family, yet he mourns for Absalom.  This verse:

6 because you love those who hate you and hate those who love you... [2Sa 19:6a ESV]

Seems like Joab was taking a big chance addressing a King this way.  Especially given that Joab is the very one that killed Absalom, against David's orders, and as such should be the one David hates.  I don't see big Joab mentioning this part of the day's events.  MSB says that when Joab says "go speak kindly to the men, or a worse evil than you have ever known will come upon you", David recognized it as a thinly veiled threat from the commander of his armies.  Joab after all had no remorse for killing Absalom.  He might also kill David.  So David goes out.

David is not immediately invited back to Jerusalem as King.  Danger is still there.  David sends word via Zadok and Abiathar to persuade the elders of Israel to invite him back.  AND, David tells one Amasa that if David comes back, Amasa will be the commander of the army in Joab's place.  Amasa was the man Absalom had set over his armies in Joab's place, to lead the fight against David and Joab.  Let us not forget that Amasa lost this battle.  Let us also not forget that Joab is the kind of man who will remember that Amasa took authority on himself against Joab, and fought against him.  Amasa is likely worried about his life, and David offers to put Amasa in charge!  Very shrewd.  David knows what is going on with Joab. 

2021 - This is a message to Joab even though David does not yet know - so far as the text tells us - that Joab is the one who killed Absalom.  But David knows that Joab threatened to kill him, or in some way discredit him.  Seems to me that Joab would have grabbed another of David's sons and promoted him to King had David not gone out.  David was wise enough not to swell up and react in the moment, but seems to be "dividing" the loyalty of the military in order to lessen Joab's influence there.

Shimei, the Benjamite who ran along cursing David as he left Jerusalem, telling David he was getting what he deserved, is the first to apologize.  David forgives him, and does not have him killed.  Mephibosheth is next.  He claims that Ziba lied about him, took the mules, and came to David, leaving Mephibosheth behind - though he wanted to come with David also.  David splits Saul's holdings between the two men but Mephibosheth says to give it all to Ziba.  Who knows what the real truth was.  The Bible doesn't say.  Perhaps the best clue to the truth is that Mephibosheth had neither trimmed his beard or nails, nor changed clothes since David left.  That seem pretty sincere to me.

As David crosses the Jordan there is infighting between Israel and Judah.  Israel wants David to stay in their part of the country, because they were the first to welcome him back as King, and they are 10 tribes to the 2 in the south.  But Judah says David is a nearer kinsman of theirs and should be in Jerusalem.  Judah prevails because "their words were fiercer".