Explain Like I'm Five

So ELI5, if you are a little baby sheep and your Shepard was out caring for the flock. He provides a vast world for you to live in but there are bad things in the world and your little sheep brain can fall easily to these bad things. Your Shepard realises there is a way he can show you to live well without him around all the time, but it takes a big sacrifice on his part. He takes a look and goes you know what, I'll be a symbol, I'll give up my Shepard life and hopefully you will see, there is a bigger picture and a greater good. So little sheep, you can live in a bad world where people do bad things and I guess everyone suffers from it. Or you too can be like your Shepard and make sacrifices to be a good sheep, and if enough other sheep do the same the flock will be a pretty good place to be. PS. I'm not Christian but I figure that's the gist of the whole thing

I'm catholic, and to me it's because behaving in a good way will simply make you live better;
the idea is that sin is something that turns you away from God, but being close to God is what makes you truly happy

So even in this life, behaving in a good way would make you live better and happier

How odd, that one should be good not for the sake of goodness, but out of fear of damnation.

Jesus is an example of an ideal person. Being literally divine Jesus is capable of setting a perfect example of love, forgiveness, and compassion. We humans are not. We have flaws, but should still strive to be good people, just as Jesus was a good human.

If you are "being good" or "not being bad" for selfish reasons, you aren't acting out of love or goodness. Heaven, hell, reward, punishment, these shouldn't matter when it comes to virtue or vice.

The “be a good person” and “you’ll be forgiven” are two separate ideas. Digging into it requires digging into a lot of different religions and their beliefs. Churches and people disagree on how those go together.

I don’t feel your request of “understanding the reasoning that Christians use” relates well to the question in your title. Much of religion now is repeating dogma rather than spiritual awareness and bettering yourself.

You have to be sorry to be forgiven. If you weren’t trying in the first place, it’s hard to be sorry.

But also, the thing isn’t designed to be balanced or suitable.

Jesus will forgive you because that’s how it works. The system wasn’t designed by humans.

What's so disheartening is that a lot of fundie Christians actually use this logic to get away with twisted stuff like SH, SA, or CSA.

(And then the next day they collectively blame drag queens for allegedly doing the exact same thing to CYA, but that's another story.)

Welp you don't want to hear it but the best explanation is religion is a system to scam commoners of their devotion and money. If things start not making sense then you should stop believing in Santa Claus

You absolutely don't have to. But when you're a Christian, you love God with all your heart, all your mind, and all your soul; and you love your neighbor as yourself. The result is that you do good works by virtue of doing God's will. Good works are a result of salvation.

Answer according to anyone christian: (note- not me) You don't. You have have to "Be sorry" and "ask forgiveness". You can still be an enormous piece of sh*t if you say you're sorry that you were bad.

You see, there are these things called eigenvalues. They dimentionalize the vector space. We can contruct a personality vector space and assign a set of orthogonal personality vectors. (Sees that this is elif). Erm, think of a "which Harry Potter character are you" quiz. We can add and subtract weighted , erm, Harry Potter characters, to get to you. You are half Harry plus two Rons minus 1.5 Malfos.

Now those numbers might change over time. That is you at that moment. If you, erm, took a DeLorean back to 1955, but still had those same numbers, you would still be you. If you wiped your memory but still had those numbers, you would still be you. Stands to reason if you went back in time and got your memory wiped, you would still be you. What if someone in the past (or future) had the exact same numbers? That would be you, even though no time travel occurred.

Now (erm, how do I explain vector projection to a five year old), ummm, if your numbers are close, you are mostly you? Now Jesus, ahh, scored a particular score on the sigh Harry Potter quiz. Remeber how I said your numbers change? Well, if your numbers are close enough, you could say that he is you, or Jesus is living Through you. And as long as more people in the future get numbers close to both yours and Jesus's, you could say you are living on, or having eternal life. And in order to change those number to Jesus's, you have to be good.

What? Oh, yes I got Hermonie. How did you know?