Abd al-Aziz ibn Baz
In December 1979, the Soviet Union invaded Afghanistan. Shortly thereafter, Abdullah Yusuf Azzam, a Muslim Brother cleric with ties to Saudi religious institutions, issued a fatwa declaring defensive jihad in Afghanistan against the atheist Soviet Union, "fard ayn", a personal (or individual) obligation for all Muslims. The edict was supported by Saudi Arabia's Grand Mufti (highest religious scholar), Abd al-Aziz ibn Baz, among others.