Surah 2. Al-Baqara, Ayah 152

The word "remember" is too pale a word for zikr, which has now acquired a large number of associations in our religious literature, especially Sufi literature. In its verbal signification it implies: to remember; to praise by frequently mentioning; to rehearse; to celebrate or commemorate; to make much of; to cherish the memory of as a precious possession. In Sufi devotions zikr represents both a solemn ritual and a spiritual state of mind or heart, in which the devotee seeks to realise the presence of God. Thus there is zikr of the mind and zikr of the heart. For beginners the one may lead to the other, but in many cases the two may be simultaneous. There is a subtler distinction, between the zikr that is open, and the zikr that is secret, corresponding to the two doors of the heart, the fleshly and the spiritual. In English some account (very imperfect) of zikr will be found in Hughe's Dictionary of Islam, covering over 14 columns.