What unity is deeper than that one of the pilgrims when they stand at the mountain of 'Arafat with bare heads and simple white clothes? There is no difference between the rich and the poor, the ruler and the subject, men and women, Arabs and non-Arabs. All of them are the same, like the teeth of the hair comb. They direct themselves towards Allah, humble and submissive.
This is their description when they make tawaf (circumambulation around the Ka'bah) and sa'y (going between the mountains of As-Safa and Al-Marwah), stay overnight at Muzdalifah and Mina, sacrifice animals, and throw stones. Similarly, this is their description when they perform the congregational prayer at the open areas or at the Holy Mosque. They pray behind one man (i.e. the imam) and supplicate to one God (i.e. Allah). They read one Book, the Qur'an, and direct themselves to one Qiblah, the Ka'bah, at the Holy Mosque. They perform the same rites of standing, sitting, bowing down, and prostration.
It is a kind of unity that penetrates the hearts, and not only external appearances. This is unity in aim and direction, in sayings and deeds, an