Christian Ethics is not a closed field. We tend to think of it as a discipline resolved in some cloister by guys with funny haircuts in the 1400s but really, it’s never been more fiery. God is not a finished subject. All those guys from the 1400s are dead. Come to think of it all those guys from the 1800s are dead and those of us from the 1900s are following fast to the same destination. The world is old but the day is new and Christian Ethics still has its vigor.
It is a field of exploration, but still, there are ground rules. You can’t start just anywhere and expect to get to somewhere useful. All those weary dead from long ago are still speaking in book and culture and if it’s “Christian” ethics that you want to know, they need to be heard, found worthy, or found wanting. If anyone fails in their definition of “Christian” or “Christianity” their understanding of “Christian Ethics” won’t be of much value.
If Christianity isn’t anything in particular, it is also irrelevant and Christian Ethics will die a deserved death of light importance. If Christianity is actually something, if the teachings of Jesus have an actual meaning that is discernible, apprehensible, and reasonable then we should with the tools at hand be able to receive from it some basic form and function that will stand as a ground to doing some actually Christian “Christian Ethics”.
With that, there are some basic themes that are universal to the adventure. There are some things that any supposedly Christian Ethicist worth their salt is going to need to bear in their interpretation and explanation of a Christian Ethics. More, there are some material sources that can’t be avoided and must be coherently incorporated into any discussion of the program and that will largely determine whether the “Ethic” will be taken as plausible or implausible. Most of these will be portions of the Biblical record of Jesus’ thoughts, words, and deeds but some of it will be ideas from history and philosophy that have become so embedded in the discussion that one cannot truly be said to be dealing with the subject matter were they avoided.
As for the texts of scripture, the Ten Commandments and the Sermon on the Mount are obvious documents of incalculable importance. As for thinkers: Augustine and Aquinas, Luther and Calvin, and Kant stand most prominently as teachers of great effect and reputation. In contemporary Christian Ethics (if it makes sense to use that as a category) to ignore the thought of Alasdair Macintyre, Stanley Hauerwas, Greg Bahnsen, Bishop Shelby Spong, Francis Schaeffer and C.S. Lewis among others is to simply not engage the subject.
In Christian Ethics, there are a lot of things going on: good things, bad things, and things that seem to defy a coherent ethical description but things are neither boring nor easy to grasp.