Our judgement of what is right and wrong (vivek) decides which deed is right and which deed is wrong. An action that harms our self or others is wrong and an action that leads to the well-being of our self and others is right.
Remember that the soul is always pure which is why every human being in reality is noble by nature. Everyone desires the truth for themselves. A liar will never want another person to lie to him/her. A thief never wants his/her house to be robbed. A murderer never desires oneself to be murdered. Also, one who insults others always expects others to respect him/her.
Your behavior towards others should be how you would like others to behave towards you. This is Dharma (righteousness). Those who provide happiness to others gain happiness themselves. No one gains happiness by making others unhappy. Those who are pleased by seeing the sorrow of others are demons and foolish. They cause self-destruction. The happiness gained by such people is transient.
Those who help others lead to their own well-being. No one can hinder one who works hard for the welfare of others.
Par hit saris dharam nahī bhāī, par pīdā sam nahi adhmāhi
Meaning: there is no virtue like benevolence and no meanness like oppressing others.
Par hit bas jinh ke mann māhi, tinh kahu jag durlabh kachu nāhi
Meaning: there is nothing difficult or impossible for those who have the well-being of others in mind.
