2Sam 13 to 15 David’s grieving over his sin and the loss of the baby born to him and Bathsheba is a turning point in David’s reign as king. God forgives, but He still allows the consequences that we might learn from them and others might as well. From chapter 11 onward, God will show us several lessons regarding sin and its consequences that we may take heed lest we too fall prey to the enemy of sin. Where scripture is silent, we are not to speculate; therefore, our questions are irrelevant to why David did not discipline Amnon or Absalom. However, we can look and heed closely how God used his children’s errors of judgment to discipline David and to draw him closer to Himself. “These things happened as examples for us, so that we will not crave evil things as they did” [1Co 10:6]
This set of chapters is not given to us to speculate, but instead to teach us how David responded in times of crisis and show us how we are to respond. Our responses to life crises show us that we are either walking with God or apart from God. We are to look into the mirror of God’s Word to see our heart. We are to take that image and remold ourselves into the image of Christ. As James says, we are quick to respond and “forget” rather than heeding the warning that the mirror has revealed.