Everything starts in the heart. And God sees the heart. We may fool man, but we will not fool God. A surrendered heart will allow God to use us.
The cross is in view. And Jesus is trusting God's plan. Will Peter trust God's plan? Will we trust God's plan?
The Christian life is a life of obedience. "Trust and obey, for there's no other way, to be happy in Jesus."
God's covenant with David is fulfilled through Jesus. God will always do what He says. All the promises of God are fulfilled in Jesus.
The cracks in Saul's life become visible. His foundation is shaky. His kingdom will not endure because his heart is not perfect toward God.