Then the king was deeply moved, and went up to the chamber over the gate, and wept. And as he went, he said thus: "O my son Absalom--my son, my son Absalom--if only I had died in your place! O Absalom my son, my son!" 2 Samuel 18:33

David wept. His household was in disarray. One of his sons (Amnon), raped a half-sister (Tamar). Tamar’s brother (Absalom), treacherously murdered Amnon. Absalom was exiled for three years to Geshur. David wept for Absalom every day (2 Samuel 13:37-38). Absalom was finally invited back to Jerusalem. He returned, but was disallowed to see His father, David. Absalom rebelled, driving David from Jerusalem. A civil war erupted. Though David demanded that Absalom be spared, he was killed. David again wept for Absalom (2 Samuel 18:33). All this (and more) is recorded in 2 Samuel 13-18.

While David’s children were responsible for their own sin, humanly speaking, so much of what went wrong in David’s family was the result of David’s many failures as a father. David was a godly man who had a heart for the Lord, but he was anything but sinless—or a good father.

Are there any lessons to learn?

Even the most godly people are still sinners.
Let us humbly acknowledge that none of us has ever come close to perfect parenting.
Let us own our failings, and give all glory to God if our children follow the Lord—in spite of our failings.
Let us refrain from criticizing others because of their children—whether the parents’ failures are the cause or not.