To change can be hard but to remain steadfast is even harder to do.

To change, we might need to fight external forces that might prevent us from changing but to remain steadfast, we must fight our own inner demons to prevent us from going back to the old ways.

Fadalah ibn Ubaid reported: The Messenger of Allah, peace and blessings upon him said, “The one who strives in the way of Allah, the Exalted, is he who strives against his soul.” 

Hadith Ahmad