Originally Posted by Getoffmyback
A useful article I found in this regard:
The suffering of the world is spoken of in terms of wars, starvation, hatred, competition, and the struggle of the survival of the fittest. Yet all the suffering of the world originates in the human heart. Every crime committed, every act of oppression, every callous cruelty, and every injustice to the self or others emanates from the hearts of men. However, for every wrong wrought by the human heart, a thousand acts of mercy have issued forth: every mother's love, every child's forgiveness, every teacher's care, and every father's concern for the well being of his progeny -- all have their source in the core of the human being, the human heart. If we are to right the world, we must first rectify our hearts, and this is why every revelation has been granted to humanity: to make firm our hearts. The most oft-recited prayer of the blessed Prophet, peace and prayers be upon him, was "O Revolver of the hearts, make firm my heart upon the straight way." In no equivocal terms, the Qur'an states, "On the day of Judgment, when neither wealth nor children will avail, only one who brings forth a sound heart."
A sound heart! The soundest of hearts was the heart of the Messenger of Allah, peace and prayers be upon him, who through his purity and singularity of intention transformed the world. His teaching remains, and the challenge is for each of us to take it and with it transform our hearts and thereby the very world in which we now reside. Time is of the essence as the diseases of the heart, so prevalent among men now, threaten the very biosphere we have been commissioned to protect.
- Shaykh Hamza Yusuf's introduction to the Purification of the Heart series of lectures