In chapter 25 we learn about the death of Samuel the prophet, and the story of Abegail the wise women who went and offered gifts to David and prevented him to sin and act out of his anger towered Nabal her husband who wasn’t wise and fair with David.
In Chapter 26 we learn about David and how he didn't repay the evil with evil and chose not to harm Saul the king, leaving the matter in God’s hand.
In chapter 26 verse 23: David said “May the Lord repay every man for his righteousness”. We learn not to revenge fir ourselves, and leave the matter to God who is just and gives everyone according to his deeds. We should have faith that God will deliver us.
** We shouldn’t take revenge for ourselves but leave it to the Lord.