The shahada (Arabic: الشهادة‎ aš-šahādah  audio (help·info)) (from the verb شهد šahida, “he witnessed”), means “to know and believe without suspicion, as if witnessed, testification”; it is the name of the Islamic creed. The shahada is the Muslim declaration of belief in the oneness of God (tawhid) and acceptance of Muhammad as God’s prophet. The declaration in its shortest form reads:

In Shia Islam, the creed is expanded with the addition of a phrase concerning Ali at the end:

The word shahādah is a noun stemming from the verb shahida, meaning “to observe, witness, or testify”; when used in legal terms, shahādah is a testimony to the occurrence of events, such as debt, adultery, or divorce. The shahādah can also be expressed in the dual form shahādatān (= "two testifyings"), which refers to dual act of observing or seeing and then the declaration of the observation. The two acts in Islam are observing or perceiving that there is no god but God and testifying or witnessing that Muhammad is the messenger of God. In a third meaning, shahādah can mean “martyrdom”, the shahid (“martyr”) demonstrating the ultimate expression of faith.

Hamza Yusuf Hanson is an American Islamic scholar, and (with Zaid Shakir and Hatem Bazian) is co-founder of Zaytuna College in Berkeley, California, United States. He is a convert to Islam, and is one of the signatories of A Common Word Between Us and You, an open letter by Islamic scholars to Christian leaders, calling for peace and understanding. He has described the 9/11 attacks as "an act of 'mass murder, pure and simple'". Condemning the attacks, he has also stated "Islam was hijacked ... on that plane as an innocent victim".The Guardian newspaper in the United Kingdom reported that he "is arguably the west's most influential Islamic scholar" and added that "many Muslims find his views hard to stomach."

Hamza Yusuf was born to two academics in Washington State and raised in Northern California. In 1977, he became Muslim and subsequently traveled to the Muslim world and studied for ten years in the United Arab Emirates, Saudi Arabia, as well as North and West Africa. Hamza Yusuf spent four years studying in the United Arab Emirates and elsewhere in the Middle East. Later he traveled to West Africa and studied in Mauritania, Medina, Algeria, and Morocco under such scholars as Murabit al Haaj; Baya bin Salik, head of the Islamic court in Al-'Ain, United Arab Emirates; Muhammad Shaybani, Mufti of Abu Dhabi; Hamad al-Wali; and Muhammad al-Fatrati of Al Azhar University in Cairo, Egypt.^{[citation needed]} After more than a decade abroad, he returned to the United States and earned degrees in nursing from Imperial Valley College and religious studies at San José State University.^{[citation needed]}