Chapter 24 has no notes from the SAB, but it's an interesting little story. In the midst of Saul and his men hunting for David, Saul happens to corner David in a cave, but doesn't realize he's done it.
Saul comes into the cave where all of David's army is, "to cover his feet". (He's covering his feet with his clothes, i.e., he's dropping his pants to take a dump.) David's men see this as a golden opportunity for David to strike Saul down, since he's totally at David's mercy, but David refuses to hurt Saul, instead cutting off a piece of his clothing.
After Saul leaves the cave, David steps out after him and shows him the piece of his clothes, sending the clear message that he could have taken Saul's life, but chose not to out of respect for Saul as the current king of Israel. This also ties back into the recurring theme of symbolism in clothing once again. Note that Saul had previously offered his clothing to David in chapter 17, but David had refused. This gesture may be implying, "I may have the right to someday take your office, but I won't take your life to get it."
Saul is apparently touched by the gesture, calling David "son" and admitting that he truly knows David is destined to be king. He asks David to be kind to his descendants after he is gone, and David swears to do so.