The Oath is a pacifistic religion that follows a single code to varying levels of strictness.
The Oath has it’s origins in the Distant History Era, though it was not until the League Era that the different religions would coalesce into the form it takes now. It was not the largest religion by any means, but it was known for it’s healers, medical workers, rescue workers, and even detectives. It was so influential in some of these circles that a minimalist version of the Oath would become a requirement to follow as a doctor within the League.
With the Civil War, those who followed the oath were split up. However those who follow it remain even into the Modern Era. They, as a group, care little for power or influence and so remain relatively few in the galactic scale of things. However even now most medical practitioners follow a form of the Oath and some are formal adherents to the Oath as religion.
The core concept of this religion is the Oath: “Do no Harm”. This applies to other people, animals, plants, and even the environment. However there are varying degrees to which one may subscribe, some versions even allowing a person to defend themselves with violence when attacked with lethal force. Most however will not eat animals and some go further and even refuse to eat plants, instead living off of non-living food supplements.
The Oath has no formal priests, nor does it require any buildings for worship.