This is a great book! It’s short and (mostly) to the point. The author looks at the parable of the Prodigal Son. While the younger brother is wrong for turning his back on his family, the elder brother is just as wrong for failing to welcome the younger son back into the family upon his return.
Dr. Keller points out that in modern times, most people focus on the younger brother because it’s easier to understand why what he did was wrong. But he points out that there many churches that are filled with “elder brothers” in that they are looking to judge other people for what they’ve done. It’s easy to fall into the trap of thinking that you obey God, therefore you deserve salvation, and other people don’t deserve it as much. But the truth is that Christianity says that we are all saved through grace – and if we weren’t, no one could “deserve” it on their own! This way of thinking is particularly dangerous because the more good you do, the more you fall into this prideful trap.
Anyway, I’d highly recommend it if you’re at all interested in Christianity.