I am a proud Christian and a believer but I do have doubts and hesitations. My biggest problem with God is this: what is sin? Even if we're fervent believers and want to serve God, how do we know what is acceptable or not? Even the Bible seems to be well aware of this difficulty: There is a way that appears to be right, but in the end it leads to death. (Proverbs 14: 12) We do know for sure that God's justice is different from ours (e.g. all sins are equally detestable in the eyes of God, whereas human justice is proportional and punishes some crimes more severely than others) and He does not compromise when it comes to His Law. Many sins have become commonplace in our society and most people today don't even see them as reproachable or negative. Nobody questions that murder and theft are sins. But what about smoking, nudity and eating certain foods? Here's another one: Catholics love images of Jesus and saints but many Christian groups consider it idolatry.