Ibn Juzay al-Kalbi began his exegesis of the Quran with an introduction to the various disciplines related to explaining the Quran. One of these topics he included is Sufism. The basic concern of Sufism is the heart: knowing its good and bad qualities, how to rid it of bad qualities, and how to instill it with the good. Sufism is connected to the Quran since the Quran mentions divine knowledge, struggling against the self ( nafs), and illuminating and purifying hearts via obtaining praiseworthy character and avoiding blameworthy character. In his work he then covers twelve of these topics: thanks ( shukr); Godfearingness (taqwa); remembrance ( dhikr); patience ( sabr); tawhid; love for Allah; reliance upon Him ( tawakkul); vigilance ( muraqabah); fear and hope ( khawf and raja); repentance ( tawbah); and sincerity ( ikhlas).