We request clarification of the statement of 'Ali (may Allah be pleased with him) as found in al-Adab al-Mufrad: "Intellect is in the heart."

The questioner : A questioner asks: Regarding the hadith of 'Ali (may Allah be pleased with him) in al-Adab al-Mufrad, "Intellect is in the heart," I ask you to clarify this for us. May Allah reward you with good.

The Shaykh : To my knowledge, the statement that intellect is in the heart is explicitly mentioned in the Noble Qur'an and in the authentic Sunnah. Earlier, we mentioned the occasion of the verse of Allah the Exalted: And in the other verse: And the famous hadith: There is no doubt that the center of intellect and understanding is the heart. This is the lump of flesh whose secrets today's doctors know only in its apparent aspect: that it is a pump that supplies the body with purified blood. That is all the doctors know. As for there being a secret within it that brings well-being to the body, not only from the material aspect—which is what the doctors mentioned earlier have discovered—but also from the spiritual and moral aspect, the Messenger (peace and blessings be upon him) says in the aforementioned hadith: The point of inquiry, given the question, is that the intellect, which doctors today and all people believe is located only in the brain; and I mean what I say when I say that all people believe the center of intellect is only the brain. I do not say they claim or assert that the center of intellect is the brain. It is true that the center of intellect is the brain, but not only that. I compare the brain, in relation to the heart and the connection of the intellect in the brain to the heart, to the connection of a water tank to its primary source.