“Moreover you know also what Joab son of Zeruiah did to me. How he dealt with the two commanders of the armies of Israel, Abner son of Ner and Amasa son of Jether. He murdered both of them, retaliating in a time of peace for blood that had been shed in war. He put the blood of war on the belt around his waist and on the sandals of his feet. Act therefore according to your wisdom, but do not let his gray head go down to Sheol in peace. Deal loyally with the sons of Barzillai the Gileadite. Let them be among those who eat at your table. They gave me such loyalty when they met me as I fled from your brother Absalom. There is also with you, Shimei son of Gera, the Benjaminite from Bahurim, who cursed me with a terrible curse on the day when I went to Mahanaim. But when he came down to meet me at the Jordan, I swore to him by Yahweh. ‘I will not put you to death with the sword.’ Therefore do not hold him guiltless. You are a wise man. You will know what you ought to do to him. You must bring his gray head down with blood to Sheol.’”
After the lovely admonitions to follow Yahweh and the Mosaic Law, David got practical with what to do about certain of his followers. It seems that what David was afraid to do during his lifetime, he wanted done after his death. He was still mad at Joab for killing Abner and Amasa during peace time for what they had done in battle. Although he had forgiven Shimei for his curses, David felt that his son should do to him the same as he hoped he would do to Joab, send both their gray bloody heads to Sheol. On the other hand, Solomon was to be kind to the sons of Barzillai, whose father had been so kind to him when he was in exile from Solomon’s brother Absalom. Revenge is sweet even if it takes another generation to get it done. So there were the blessings and the curses of David. There is no great speech, just the admonitions to Solomon.