II Samuel - Chapter 21
Famine, Vengeance, and an Unusual Number of Fingers and Toes
There was a three-year famine during the reign of King David. (The commentators disagree as to whether this incident occurred at this time in the narrative or earlier.) David inquired of G-d as to the cause and he was told that there were two reasons. First, it was because Saul was not properly eulogized and second, it was because Saul had killed (or tried to kill) the Gibeonites. (These two reasons may seem contradictory, but it's important to note that, for all his flaws, Saul was still a righteous person. Righteous doesn't mean perfect.)
You may recall that the Gibeonites tricked their way into a pact with Joshua and were servants to the Tabernacle. There is no recorded incident in which Saul persecuted Gibeonites. Either he figured that Joshua's deal of protection had expired and he actively tried to kill them, or many were killed as "collateral damage" in Nov, or by killing the Kohanim of Nov, he had deprived the Gibeonites of a living. In any event, David called the Gibeonites and asked what he could do to square things. "Not much," they replied, "Just kill seven of Saul's descendants and we'll call it even!" This goes against the normal due process; David used his extra-legal authority, with G-d's indication that it was appropriate to do so.
So David gave the Gibeonites seven descendants of Saul, but not including Mephiboshes, who was under protection of his oath to Jonathan. They were killed and the corpses were publicly displayed. (Again, not normally permitted, but deemed necessary here as a warning not to mess with the Gibeonites.) Ritzpah, the mother of two of the victims, made a makeshift tent and kept a vigil over the corpses. She scared away birds by day and animals by night. When David heard about the dedication she was showing to the deceased, it inspired him how to rectify the other problem: that of not properly eulogizing Saul. David had the remains of Saul and Jonathan exhumed and reburied in a place of honor. While it was too late to officially eulogize them, David was able to eulogize them incidental to the seven victims.
Now, about Ira, David's "personal Kohein" from the end of the last chapter. The Talmud in Eruvin (63a) says that the juxtaposition between Ira and the famine is a message. If a person gives all his "priestly portions" to one Kohein, he brings about hunger, as other Kohanim will have nothing. So our actions in the micro affect the world in the macro.
The chapter ends with a description of various Philistine giants that were killed by David and his men. David had lost his fighting edge, so his men retired him from the battlefield and Avishai killed the giant Yishbi-b'nov. In another battle, a soldier named Sibchai killed Saff. In yet another battle, Elchanan of Bethlehem killed Goliath. (We know that David killed Goliath; presumably Elchanan is another name for David, as per the commentary of Rashi and others. The corresponding verse in I Chronicles (20:5) says that Elchanan killed Goliath's brother, Lachmi. Take your pick.) Finally, David's nephew Yehonason killed an unnamed giant who had six fingers on his hands and six toes on his feet, for a total of twenty-four digits.
The commentators all ask why the Navi has to give us the math; can't we figure out that the giant had twenty-four digits? The answer is that if it said "six fingers and six toes" we might mistakenly think that there were three on each hand and foot, total twelve. If it just told us twenty-four, we might think there was one regular hand and foot of five each and one deformed hand and foot of seven each. This way we know, 6 + 6 + 6 + 6 = 24. (Of course, why it's important to have this information at all is still something of an enigma.)