According to the infidel Wikipedia:

Although the Iranian revolution's leader, Ayatollah Khomeini, was very much in favor of Shia–Sunni unity, he also challenged Saudi Arabia, in his view an "unpopular and corrupt dictatorship" and an "American lackey" ripe for revolution. In part because Saudi Arabia was the world's major international funder of Islamic schools, scholarships, and fellowships, this angered not only Saudi Arabia but its many fundamentalist allies and benefactors throughout the Arab world, according to Nasr.[93]

Another effect noted by political scientist Gilles Kepel, is that the initial attraction of the Islamic Revolution to Sunnis as well as Shia, and Khomeini's desire to export his revolution motivated the Saudi establishment to shore up its "religious legitimacy" with more strictness in religion (and with jihad in Afghanistan) to compete with Iran's revolutionary ideology.[94] But doing so in Saudi meant a more anti-Shia policies because Saudi's own native Sunni school of Islam is Wahhabism, which includes the prohibition of Shia Islam itself, as strict Wahhabis do not consider Shia to be Islamic. This new strictness was spread not only among Saudis in the kingdom but thousands of students and Saudi funded schools and international Islamist volunteers who came to training camps in Peshawar Pakistan in the 1980s to learn to fight jihad in Afghanistan and went home in the 1990s to fight jihad. Both groups (especially in Iraq and Pakistan) saw Shia as the enemy.[95][96][97] Thus, although the Iranian revolution's leader, Ayatollah Khomeini, was very much in favor of Shia–Sunni unity, and "the leadership position that went with it",[98] his revolution worked against it.