Prayer callus

A prayer callus, zabiba or zebiba (Arabic: زبيبة zabība, "raisin") is a callus on the forehead present in some devout praying Muslims, mainly in Egypt.[1] Owing to its societal significance it is also known as the "devout sign".[2] Among notable Egyptian leaders Anwar Sadat's reputation for personal piety was evidenced by a callus on his forehead from repeated prostration in prayer.[3]

A pilgrim with prayer bump photographed outside Masjid al-Haram.

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. It is mentioned 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[4]

Some Muslims also believe that on the Day of Resurrection, this callus will fluoresce with an immense white light.[5] However, riya (showing-off) is prohibited in Islam; if the prayer bump may result in riya, it is recommended to take precautionary measures to stop a bump forming, as worship may be deemed void due to riya.

In extreme cases, the callus can be thick enough to create a noticeable bump that protrudes from the forehead.