When God changes someone's heart, when that person says yes to following Jesus, it is a powerful thing. Because it can change not just that one person, but everyone they meet. I don't know if any of us would be here today if God hadn't changed Paul's heart to spread the good news of a loving God not only to the jailer in Philippi, but to churches around the Mediterranean. When God changes a heart it's like the giggles. Have you ever caught the giggles? What happens? They're hard to get rid of! And they start to spread, until soon enough the whole room is giggling, whether they know why or not. That's how God's love spreads - it starts with one person, and if we let it, spreads and spreads and spreads.