"Since this holiday overlaps with the pilgrimage or the Hajj to Mecca, which takes place in Saudi Arabia, many people will look to Saudi Arabia to determine the timing of this holiday," Khalil told USA TODAY. "In Saudi Arabia, there will usually be a select group of people looking for the new moon."
The day of celebration varies for different countries and even communities. In the United States, most celebrations will begin the evening of July 19.
“Al-Adha” refers to sacrifice, specifically the “one in which Abraham was asked – as a test – by God to sacrifice his son, only to have God intervene and substitute a ram (or lamb) instead,” Omid Safi, professor of Islamic studies at Duke University, said.
The sacrifice as depicted in the Quran (the Islamic holy text) has similarities to what’s in the Bible, though according to most Muslims, Abraham is asked by God to sacrifice his son Ishmael, not Isaac.