The central doctrine of Islam is al-tawhid, Unity. God is One; there is no god but God. And the Unity of God is reflected in the universe, in the unity of nature’s laws, as well as in the uniqueness of each object in nature. To construct circles is to make a geometrical diagram of al-tawhid.
The Arabic word for ‘heart’, qalb, is derived from the root QLB or QBL, which embraces a number of concepts having to do with ‘turning’. In Sufi metaphysics the Heart is the centre of the psyche, the point at which it is intersected by the vertical ray of the Spirit (ruh). This symbolic image has obvious affinities with the act of constructing a circle using a compass and a sheet of paper. The Heart is who we really are in the sight of God; it is the central point of our full and authentic humanity. Whoever wants to rise along the vertical path of the Spirit, the axis mundi, first has to have reached the Centre, the Heart, which is another way of saying that we can’t relate to God with only a part of ourselves. A line drawn from any point on the circumference of a circle so as to intersect a line passing vertically through the circle’s centre can never be one with the infinite elevation which the vertical line symbolises. It must intersect the vertical line at some point short of infinity. Furthermore, it only ‘represents’ its own point-of-origin on the circumference; it can in no way stand for the circle as a whole. But the centre of the circle does stand for the whole circle, since it is the point from which the circle expands, and to which it returns. And only the central point of the circle is available to the ray of infinite elevation which symbolises the relationship between the human form and God. It is said that God holds the Heart between His fingers, and turns it however He will. This is a way of saying that the Heart is the reality through which we can see how all the changes-of-state we experience in passing time have the same Point-of-Origin; that change on the horizontal plane is an expression of permanence on the vertical one; that the waqt, the present moment of spiritual time, is the manifestation of God’s eternity in the created world. And just as God turns the Heart however He will, so the Heart is the point through which and by which the human soul returns to God on the spiritual Path; it is the spiritual Kaaba, the qiblah toward which we turn.