Reddit reviews Christian Ethics: A Very Short Introduction

Christian here!

The basic principle of our faith is that Christ is God and became man to (somehow) defeat sin and death through his execution and resurrection. Ethics are secondary to that.

Some varieties of Christians don't think ethics should have any role in the faith (as they'd be "law" and not "grace"), so will mostly pick up their ethics from secular sources. The teachings of Christ are interpreted as unachievable goals that are genuinely good, but are intended to make you see that you can't free yourself from the effects of sin by your own efforts. This was a mostly unintended side effect of the more hardcore parts of the Reformation.

Other varieties think that's all mostly wrong. It's one of those "Eh I can see what they're saying, but no" types of things. However, they still generally will take a prudent approach to the teachings of Christ, which often demand a sort of vague perfection. It's not the teachings that are confusing, it's how to reliably translate them into reality. Even in the Bible, St Paul gave different advice to different churches. And how do you translate Jesus's apparent pacifism when it's the Army general who becomes a Christian? How do you navigate real life situations where both options result in bad outcomes? Do you violate the Ten Commandments and lie to Nazis if it saves Jews? That sort of thing.

Roman Catholics have (mostly) adopted a mashup of Jesus's teachings, the Ten Commandments, and Aristotle's classical virtue ethics in their attempt at it. They still have a several hundred page document (the Catechism) that goes over the basics.

And but so, there's never been a Christian ethic that all Christians have adopted. Charity to the poor and oppressed approaches that, though, being probably the oldest Christian ethic. Most Christians today still think that's very important, if not primary.

Conservative American Christians still think they're being good to the poor. They do give a lot to charities, and they really do believe that laissez-faire capitalism really is the best shot the poor have to improve their lives in the long term.

ETA: Oxford's Very Short Introductions series, which I love, has a great volume on Christian Ethics. Like most of the VSIs, it's rather dense and doesn't shy away from using technical terms after introducing them once, but it's a great overview of what exactly might constitute "Christian ethics". It's written partly in response to claims by Sam Harris that Christianity is inherently unethical.