Religion might contribute something towards the field of ethics if religious people were to practice what they preach. All too often, though, that simply does not happen - and it matters not what the religion is, either (despite widespread claims that "our church don't do that sort of thing"!)
This fact was not lost on the newly-converted Maori people of 19th Century New Zealand. They were quick to observe how the Ten Commandments got relegated to second place between Monday morning and midnight Saturday - then sent on an indefinite Leave of Absence whenever there was a war on.
In his Seven Habits of Highly Effective People, Stephen Covey noted that to determine which principles are correct, you only have to visualise the results if everyone did the opposite. It doesn't take either the threat of hellfire or the reward of heaven (or the ravings of some half-mad religious leader!)