It was normal, natural, and right for David to grieve over the actions of his son, his own failures as a parent, and the death of his son - as a father. But a King does not have the same luxury. Absalom tried to steal the throne from his father, and David's men fought for him and won the victory, but his very public grief made them feel shame instead of being able to celebrate their victory. As a King, David did not handle this right, and Joab confront him on it. In this case, David should not have allowed his feelings to dictate his behaviour as king.
This is a good reminder for us that our actions should not rely on our feelings. Our feelings are not necessarily bad, but they are also not necessarily good. Our feelings can betray us. We need to filter our feelings first through the Word of God - where our feelings and the Word are at odds with each other, we must realign ourselves to the Word, not to our feelings. Even when our feelings are in line with God's Word, we still need to act on those feelings in both a godly manner and as a steward of the position God has given us.
In our NT passage I appreciated the reminder that we cannot value or love anything (even good things) above God.
Tomorrow's Bible In a Year Passage: 2 Samuel 21-22; Luke 18:24-43