The eternal dharma (religion) of a man is to perform good karma. Karma is the act or work you perform and the outcomes thereof. Dharma or religion shows the path of truth. Whatever your religion the good karma of a man is to follow the true path and to render service to the others.
( the picture I scanned from a framed photo).

We should believe in karma. Good karma shows good consequences and bad karma shows bad consequences. Planting a banyan tree we can't expect mangoes from it. This example shows the meaning of well known quote -"whatever we sow that will reap". If your work or act hurt someone then you will suffer from repentance.Your mind get cool and it fill with happiness if you follow the path of eternal dharma.

Hopefully you will like my post.

Please upvote for me.

WITH REGARDS
@hemantasarmah