Qalb

In Islamic philosophy, the qalb (Arabic: قلب) or heart is the center of the human personality.

The Quran mentions "qalb" 132 times and its root meaning suggests that the heart is always in a state of motion and transformation.

According to the Quran and the traditions of Muhammad, the heart plays a central role in human existence, serving as the source of good and evil, right and wrong.

The heart is also a medium for God's revelations to human beings, and is associated with virtues such as knowledge, faith, purity, piety, love, and repentance.

The word's root meaning denotes concepts of change, transformation, and fluctuation, implying that the heart is constantly in motion and may undergo reversal or alteration.

These diverse uses of the word imply that its original meaning - involving ideas of turning, changing, and overturning - remains relevant, as the heart is regarded as the source of good and evil, right and wrong.

Without God's purification, the heart can become plagued with negative attributes such as sickness, sinfulness, evil, and hate.

The Quran teaches that God has sent down a beautiful scripture, and those who fear Him tremble when they read it, causing their skin and hearts to soften.

According to Seyyed Hossein Nasr, modern society rejects the importance of heart-knowledge because it fails to recognize the existence of individuals beyond their individualistic levels of being.