Ok, so what is the purpose of Hippocratic Oath? Why we have such things as Bar Association for lawyers? Statements are important - at least you have to fight

Ok, so what is the purpose of Hippocratic Oath? Why we have such things as Bar Association for lawyers? Statements are important - at least you have to fight with your inner feeling that "you lied" to all when it actual status quo its just "matter of perspective" bending morals