Many are aware that the Quran is concerned with religious life as well as matters related to both individual salvation and the social order, but fewe… - Hossein Nasr

The heart is first of all the center of our being on all the different levels of our existence, not only the corporeal and emotive, but also the intellectual and spiritual. It is what connects the individual to the supra-individual realms of being. In fact, if in modern society heart-knowledge is rejected, it is because modernism refuses to see man beyond his individual level of existence. The heart is not a center of our being; it is the supreme center, its uniqueness resulting from the metaphysical principle that for any specific realm of manifestation there must exist a principle of unity. The heart is the barzakh or isthmus between this world and the next, between the visible and invisible worlds, between the human realm and the realm of the Spirit, between the horizontal and vertical dimensions of existence. In the same way that the vertical and horizontal lines of the cross, itself the symbol not only of Christ in Christianity but also of the Universal Man (al-insan al-kamil) in Islam, meet at only one point, there can be only one heart for each human being, although this single reality partakes of gradations and levels of being. The heart, then, is our unique center, the place where the supreme axis penetrates our microcosmic existence, the place where the All-Merciful resides, and also the locus for the Breath of God. Hence the profound relation that exists between invocatory prayer carried out with the breath and the heart.

The fullest meaning of the intellect and its universal function is to be found in the ma‘rifah or gnosis, which lies at the heart of the Islamic revelation and which is crystallized in the esoteric dimension of Islam identified for the most part with Sufism. There are verses of the Quran and hadiths of the Prophet that allude to the heart as the seat of intelligence and knowledge. The heart is the instrument of true knowledge, as its affliction is the cause of ignorance and forgetfulness. That is why the message of the revelation addresses the heart more than the mind as the following verses of the Quran reveal: O men, now there has come to you an admonition from your Lord and a healing for what is in the breasts (namely the heart) and a guidance, and a mercy to the believers. Surah (10:57) (Arberry translation)

Through the downward flow of the river of time and the multiple refractions and reflections of Reality upon the myriad mirrors of both macrocosmic and microcosmic manifestation, knowledge has become separated from being and the bliss or ecstasy which characterizes the union of knowledge and being. Knowledge has become nearly completely externalized and desacralized, especially among those segments of the human race which have become transformed by the process of modernization, and that bliss which is the fruit of union with the One and an aspect of the perfume of the sacred has become well-nigh unattainable and beyond the grasp of the vast majority of those who walk upon the earth. But the root and essence of knowledge continues to be inseparable from the sacred for the very substance of knowledge is the knowledge of that reality which is the Supreme Substance, the Sacred as such, compared to which all levels of existence and all forms of the manifold are but accidents.