For one will scarcely die for a righteous person—though perhaps for a good person one would dare even to die— but God shows his love for us in that while we were still sinners, Christ died for us. (ESV)
There is an old song that has the lyric, "Everybody wants to go to heaven, but nobody wants to die." Very few people are willing to lay down their life, for any reason. There are brave men and women who will go off to war and fight for their country. Some will sacrifice their lives for a relative, but as Paul says, dying for another person is a rare occasion.
Paul argues that the rare occasion in which someone will die for another would be for a righteous person, or maybe for a good person. Consider what you already know from what Paul has said in the Book of Romans. Is anyone righteous? Is anyone good? The answer is NO! It would be a rare thing for someone to die for a righteous person, or even a good person. We are neither.
God enters the situation and demonstrates what true love is. He looks at us in our our sin. He is repulsed by our wickedness. We are in complete rebellion to his law. We have rejected him and have become completely worthless. Recognizing no worth or merit in our lives God loves us. In spite of our wickedness, Christ dies for us.
If you are not completely amazed at the sacrifice of Christ on your behalf you are likely holding on to a false understanding of you own idea of goodness. Christ did not die for you because you were righteous. He did not die for you because you were even good. He died for you because you were dead in your wretched sins and he brought you to new life.
Consider just how sinful your nature is. Now consider the incredible sacrifice of God on your behalf. Take a moment to praise him for his indescribable gift of self-sacrifice.