Faith has both apparent and hidden aspects. Its apparent aspect is when it is related by the tongue and acted upon by the body. The hidden aspect is the acknowledgment of the heart, and its submission and love. Therefore, the apparent aspect of faith will be of no use for someone who does not have the hidden aspect, though his blood is spared and his wealth and children are preserved by it. And no hidden aspect will be of any use, unless there is no fear that it will be weakened, coerced or in fear of being ruined. Therefore, the failure of apparent deeds without the existence of any real prevention, means the corruption of the hidden aspect and lack of faith. Its deficiency refers to its deficiency of faith and intensity refers to its intensity of faith.
Therefore, faith is the heart and core of Islam, and certainty is the heart and core of faith. Any piece of knowledge or deed that does not make faith and certainty stronger is abnormal, and any faith that does not urge one to perform good deeds is abnormal.
Source: Al-Fawaaid – A COLLECTION OF WISE SAYINGS – Imam Ibn AI-Qayyim,
Rendered into English by: Bayan Translation Services