Things That Nullify One's Islaam

Stated Shaykh Saalih al-Fowzaan in his introduction:

"Knowledge of them (the nullifiers) is very important for the Muslim, so that he can stay away from them and be warned about them. And also if the Muslim is not aware of them, then it is feared that he may somehow fall into one of them. It is an issue of great significance and extreme importance, since they are the very things that nullify one's Islaam and invalidate it. So then knowledge of the reasons for apostasy is very important."