Actually, the conversation would go like this.

Kid: Dad, someone on the internet said Jesus dies for our sins.

Dad: What do you think of that?

Kid: I'm not sure but it's weird. How can someone dying have anything to do with the bad things that other people do?

Dad: It only makes sense if you understand that back then, they used to kill animals as a sacrifice to God. They believed that God will show them more favor, the larger the sacrifice. If you do something God doesn't like, killing something will make God happy with you again.

Kid: This is getting more bizarre, and creapy.

Dad: So, Christians believe that Jesus was sacrificed to forgive all humans for all the bad things they do so God will be happy with them again.

Kid: O...K... So, we're all forgiven for everything we do.

Dad: Not exactly. You have to feel bad about it and ask Jesus to forgive you. If you're Catholic, you have to go through a priest.

Kid: David cries when he has to go talk to the his priest.

Dad: Yeah, that's a different topic, but that's what they believe.

Kid: Why does God want them to kill things?

Dad: It seems that he changed his mind. Somehow, since killing his "son" was such a big deal, that he's happy with us without further killing.

Kid: Is God supposed to be smart?

Dad: They believe that he knows everything and makes everything happen.

Kid: Isn't he suppose to help good people and punish bad people?

Dad: We'll get there later, your question was about sacrifice. Have you heard of communion?

Kid: Isn't that when they drink juice and eat a cookie.

Dad: That's right. The cookie is supposed to be the body of Jesus, and the juice is supposed to be his blood.

Kid: Seriously?!

Dad: Yes. It's symbolic cannibalism. According to the bible, Jesus told them to do it.

Kid: Like half the kids as school and all of their families do that!

Dad: Yup. Pretty weird.