SHAHĀDAH is a term used in Islam to denote the all-important confession or affirmation of the unity of God and the apostleship of Muḥammad. It derives from the Arabic root shahida, meaning "to attest," "to give decisive word," hence "to acknowledge as true," and is used in referring to eyewitness testimony or other dependable evidence. The same root yields one of the names of God in Islam, al-Shahīd, "the one whose word is authentic," a term used in the Qurʾān in contrast to al-Ghāʿib, "the one in hiddenness" or simply "hiddenness."

For Muslims, the term shahādah means giving open, verbal evidence of what is incontestably true. "I bear witness," the phrase runs, "that there is no god but God, and Muḥammad is the messenger of God." The Arabic reads "Ashadu an lā ilāha illā Allāh...