Our OT passage is a huge reminder of the consequences for disobedience. Yes, there is grace and forgiveness when we genuinely repent, but that doesn't nullify the consequences of our sin. Saul disobeyed God and paid the price by the loss of his kingship - though the punishment was not immediate. Today, many people mistake God's patience for lack of judgment and presume upon His grace, not realizing that the day will come when time will be up and judgment will come.
In our NT passage we see that the two greatest commandments can be summed up in four words - love God, love people. The words are simple, but living them out is definitely not always easy. We also need to make sure we are defining love the way the Bible defines it, not the way the world defines it.
Tomorrow's Bible In a Year Passage: 1 Samuel 17-18; Luke 11:1-28