After the death of Saul, David is set to take his place as king of Israel. David has the approval of God, even receiving the anointing, like Saul did. It is explained to us that God has found in David a "man after his own heart," but when we read the story of how David rises to power, we wonder how is David any different than Saul?
David's rise to power is a path that is covered with the blood of his opponents. He leads the people in war against their enemies and in this way, he is being the kind of king the people wanted; a king who would make them like the other nations.
But at the same time, David's kingship is vastly different than the kingship of Saul. We see flashes of compelling spiritual leadership, namely, his bringing the ark back to Jerusalem, his kindness and commitment to Jonathan's remaining family, and ruling over the people in a just and righteous way.
Added the story of David that we read in 2 Samuel, is the Psalms, which we have also been reading. Many of the Psalms we have up until now were written by David. Furthermore, many of the Psalms have the added benefit of including a little information about what David was going through when he wrote them.
What I take away from all of this is that David was far from a perfect man or king. In fact, if we were to measure David's moral failures against Saul's moral failures, it honestly could go either way! But what sets David apart from Saul is that David demonstrates true depth of faith in God, even in spite of his many failures.
It has always been about faith. Knowing God, and being humble enough to trust him. How difficult it must be for a king to have faith and not be driven by fear and power! David was not perfect, he was pretty far from it, but he had faith in God. This is not to excuse the things that he did, we will see in the story that God doesn't let David off the hook in the slightest! But it does remind us that faith is what God is really looking for in all of us.