Eid al-Adha' (Arabic: عيد الأضحى‎ ‘Īd al-’Aḍḥá, IPA: [ʕiːd al ʔadˁˈħaː], "feast of sacrifice") or "Festival of Sacrifice" or "Greater Eid" is an important religious holiday celebrated by Muslims worldwide to commemorate the willingness of Abraham (Ibrahim) to sacrifice his son Ishmael (Isma'il) as an act of obedience to God, before God intervened to provide him with a sheep to sacrifice instead.

Eid al-Adha is the latter of two Eid festivals celebrated by Muslims, whose basis comes from Sura 2 (Al-Baqara) Ayah 196 in the Qur'an. Like Eid ul-Fitr, Eid al-Adha begins with a Sunnah prayer of two Raka'ah (units) followed by a sermon (khuṭbah).

The word "Eid" appears in Sura al-Mai'da ("The Table Spread," Chapter 5) of the Qur'an, meaning 'solemn festival'.

Eid al-Adha is celebrated annually on the 10th day of the 12th and the last Islamic month of Dhu al-Hijjah (ذو الحجة) of the lunar Islamic calendar. Eid al-Adha celebrations start after the Hajj, the annual pilgrimage to Mecca in Saudi Arabia by Muslims worldwide, descend from Mount Arafat. The date is approximately 70 days (2 Months & 10 days) after the end of the month of Ramadan, i.e. Eid-ul-Fitr. Ritual observance of the holiday lasts until sunset of the 13th day of Dhu al-Hijjah.

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]}