In ethics there are three parts to look at: the agent, action, and outcome.
then comes schools of thought which focus on each. here is a super-sloppy and quick intro to each:
the agent: Virtue Ethics like those proposed by Thomas Aquinas and others focus on the person as the source. this then becomes a discussion on the inherent nature of humanity being good or bad? Christians have always been divide on this but Augustinian thought seems to dominate and Calvin and Luther have picked up on the Bad part and run rampant with it. but some secular humanist and other faiths study this way too. like the Dali Lama and Tibetan Buddhism is largely concerned with the private transformation and buddha-like nature of the person.
the action: deontology is the idea that only moral means can make moral ends. you can't steal or kill at all. this can lead to some harsh laws like those followed by Javert in pursuing Jean ValJean and no room for transformation. one proponent of this style is Immanuel Kant. check out this video, it does a decent job, although not altogether accurate introduction (much like this one!):
the outcome: teleology is the idea that the ends justify the means. so one can steal bread to end starvation or murder for self-defense... however, this can also lead to apologetic measures like bombing for peace or conversion by the sword that Mulsim and Christians are particularly guilty of. it's a little more open to transformation and takes into account circumstances and context.
here's Eve explaining Teleology:
what do y'all think? which do you subscribe to?