Shaykh ‘Alee Naasir al-Faqihee (hafidahullah) said,

“These [are] Four Rules(1),that the Muslim benefits from throughout his life. And they address affairs of creed, and it is known that if the creed is correct and sound, everything else [will also be] correct.

Because the Messenger of Allah informed us that,

“ There is a morsel of flesh in the body, if it is sound, the whole body is sound. And if it is corrupt the whole body is corrupted, and it is the heart.”(2)

Therefore, if the heart is sound, then all of the limbs are in obedience; meaning the heart is (like a) king and the limbs are (like) soldiers. When the heart is righteous it does not reach out except to good, and it does not perform except [that which is] good.”

The first lesson of the Shaykh’s explanation of Al-Qawā’id Al-‘Arba’a,

(1) Al-Qawā’id Al-‘Arba’a authored by Shaykh Al-Islām Muhammad ibn ‘Abd Al-Wahhāb (rahimahullāh)
(2) Bukhāri & Muslim