Dhikr, also spelled Zikr, (Arabic: “reminding oneself,” or “mention”), ritual prayer or litany practiced by Muslim mystics (Ṣūfīs) for the purpose of glorifying God and achieving spiritual perfection. Based on the Qurʾānic injunctions “Remind thyself [udhkur] of thy Lord when thou forgettest” (18:24) and “O ye who believe! Remember [udhkurū] Allāh with much remembrance” (33:41), the dhikr is essentially a “remembering” of God by the frequent repetition of his names. Originally a simple recitation of the Qurʾān and various religious writings among ascetics and mystics, the dhikr gradually became a formula (e.g., lā ilāha illa ʾllāh, “there is no god but God”; Allāhu akbar, “God is greatest”; al-ḥamdu līʾllāh, “praise be to God”; astaghfiru ʾllāh, “I ask God’s forgiveness”), repeated aloud or softly, accompanied by prescribed posture and breathing. As the Ṣūfī brotherhoods (ṭarīqahs) were established, each adopted a particular dhikr, to be recited in solitude (e.g., following each of the five obligatory daily prayers) or as a community. The dhikr, like fikr (meditation), is a method the Ṣūfī may use in his striving to achieve oneness with God.