(31) If you avoid the major sins which you are forbidden, We will remove from you your lesser sins and admit you to a noble entrance [into Paradise].
Major sins: polytheism (Associating anyone with Allah), disobedience to parents, killing a self, and perjury/making false statements.
I asked the Messenger of Allah (PBUH): Which sin is the greatest? He said: To make a rival to Allah, though he created you. I said: Then what? He said: Then to kill your son for fear that he will eat your food. I said: Then what? He said: To commit adultery with your neighbor’s wife.
