Question: What is the nafs?

Answer: It can refer to the inner self, or the base self and ego that commands to evil.

Question: What is the fitrah?

Answer: The fitrah is our spiritual nature, the realm within us that commands towards the good and Allah. 

Question: What is the pure heart?

Answer: The pure heart is a heart that is empty of sin and completely submerged in the remembrance of God.

Question: What happens when we refuse the whims of the nafs?

Answer: Your fitrah or spiritual nature becomes stronger. You become more disciplined in life. 

Question: How do we win the battle against the Nafs?

Answer: By starving it and feeding the fitrah instead.