The heart is the foundation. Whatever knowledge and will it contains necessarily extend to the body; the body cannot fail to carry out what the heart wills. Hence the Prophet, peace and blessings be upon him, said in an authentic hadith:
“Indeed, within the body is a piece of flesh: when it is sound, the rest of the body is sound, and when it is corrupt, the rest of the body is corrupt. Indeed, it is the heart.”
Abū Hurayra said: “The heart is a king, and the limbs are its soldiers. When the king is good, its soldiers are good; when the king is corrupt, its soldiers are corrupt.”
Abū Hurayra’s statement offers an approximate analogy, whereas the Prophet’s words, peace and blessings be upon him, explain the matter more clearly. Even when a king is righteous, his soldiers have a will of their own by which they may disobey him. The reverse is also possible: they may be righteous while he is corrupt, or corrupt while he is righteous. The heart is different: the body follows it and never departs from its will, as the Prophet, peace and blessings be upon him, said:
“When it is sound, the rest of the body is sound, and when it is corrupt, the rest of the body is corrupt.”
Thus, when the heart is sound through the faith within it—both knowledge and the heart’s actions—the body must necessarily be sound in outward speech and deeds, embodying faith in its full sense. As the leading scholars of hadith have said: “It is speech and action: inward and outward speech, and inward and outward action.” The outward follows the inward and is inseparable from it: whenever the inward is sound, the outward is sound; when it is corrupt, the outward is corrupt.
For this reason, one of the Companions said of a man fidgeting in prayer: “Had this man’s heart been humble, his limbs would have been humble.” The heart’s faith must therefore include love for Allah and His Messenger, and Allah and His Messenger must be dearer to a person than anything else. Allah, exalted is He, says:
“Among the people are those who take others besides Allah as equals, loving them