Prayer callus

A prayer callus, prayer bump, zabiba or zebiba (Arabic: زبيبة, romanized: zabība, lit. 'raisin') is a callus on the forehead caused by repeated ritual prostration, usually in Islamic prayer.^[1] Owing to its cultural signal of piety, it is also known as the "devout sign".^[2]

Islam requires its adherents to pray five times a day (known as salat), which involves kneeling on a prayer mat and touching the ground (or a raised piece of clay called turbah by the Shia) with one's forehead. When done firmly for extended periods of time, a callus – the "prayer bump" – can develop on the forehead which may be considered as a sign of piety and dedication. Some Muslims believe that it is referred to in the Quran as:

Muḥammad is the Messenger of Allah; and those with him are forceful against the disbelievers, merciful among themselves. You see them bowing and prostrating [in prayer], seeking bounty from Allah and [His] pleasure. Their sign is in their faces from the effect of prostration [i.e., prayer]. That is their description in the Torah. And their description in the Gospel is as a plant which produces its offshoots and strengthens them so they grow firm and stand upon their stalks delighting the sowers – so that He may enrage by them the disbelievers. Allah has promised those who believe and do righteous deeds among them forgiveness and a great reward^[3]

Some Muslims also believe that on the Day of Resurrection, this callus will fluoresce with an immense white light.^[4] With the growing popularity of the zabiba in Egypt, its visibility can enhance societal standing and reflect an individual's commitment to prayer, creating a favorable first impression.^[1] In some cases, the callus can be thick enough to create a noticeable bump that protrudes from the forehead.^[1]