Since power remained firm in the hands of the Quraysh group, and they limited their ranks to those who had refused to pay allegiance to Ali b. Abi Talib, Ali bore the brunt of this group’s enmity.
The only individuals who could move up in the ranks were those who had refused to pay allegiance to Ali – people such as al-Mugheerah b. Shu’bah, Amr b. al-Aas, Abu Musa al-Ashari, Sa’d b. Abil Waqqas, Mu’awiyah b. Abu Sufyan, Abu Huraira, Utbah b. Abu Sufyan, Sa’ed b. al-Aas, and al-Waleed b. Uqbah.
For forty years, the leadership who bore deep animosity towards Ali, forced mercenary speakers to ascend the pulpit and curse him in addition to the daughter of the Holy Prophet and their children, Hasan and Husayn. If anyone ventured outside of this jurisdiction and tried to mention the virtues of Ali, they were warned that that was a crime punishable by death. This forced scholars, such as Hasan al-Basri to refer to the fourth caliph, Ali, as “Abu Zaynab (the father of Zaynab).” Their vindictiveness continued despite the agreed upon saying of Prophet Muhammad, narrated by both Sunni and Shia that, “O Ali, no one likes you except a believer, and no one hates you except a hypocrite.”
Ali was of such a high status in the sight of the Holy Prophet that when Surah al-Bara’at (The Disavowal, also known as al-Tawbah (The Repentance)) was revealed, the Prophet sent Abu Bakr as the amir (caravan leader) of the Hajj to recite it (and thus to offer the Quraysh a stern warning). However while on the way to Mecca, Abu Bakr was intercepted by Ali b. Abi Talib through the Divine decree given by Allah to Prophet Muhammad. The Angel Gabriel instructed the Prophet with Allah’s order, “No one delivers on your behalf except yourself or a man from you.” Afterwards the Prophet commented, “Ali is from me, and I am from him, and no one delivers (the revelation) except me or Ali.”
In reality, the intense opposition towards Ali b. Abi Talib proves that without a doubt, the Quraysh group did recognize that Ali was bound to succeed the Prophet. What other reason could they possibly have had for ritualizing invocations against him? If nothing else, he was a companion with the highest recorded caliber of service to Islam and the Prophet. He was the father of the Prophet’s grandchildren and he was never known to have committed any wrong act. Although he maintained that the caliphate should have gone to him, he did not raise arms, and he only assumed the caliphate after the institution itself had crumbled. Had he been only a mere contender, the ruling powers would have exiled him – even annihilated him, just as they did to companions such as Abu Dharr al-Ghifari.
Instead, the Quraysh group was more concerned with assassinating the character of Ali, and in hindsight, their propaganda campaign points all the more clearly to the reality that they were trying to cover up the Prophet’s command that Ali was to be his successor.
In the end, this intense hatred turned into violent bloodshed when the wife of the Prophet, Lady Aishah, despite having been warned by the Prophet not to transgress against Ali, mobilized 30,000 fighters and marched from Madinah to Basra in a confrontation known as the Battle of Camel (Battle of Jamal). Lady Aishah instigated the first battle in Islam in which Muslims raised swords against one another, and as a result, she caused the death of 20,000 Muslims from her side and another 500 from the defense of Ali’s army.
Following her lead, Mu’awiyah also took arms against Ali during his caliphate resulting in the Battle of Siffeen, in which 70,000 Muslims lost their lives. Indeed, she did not take heed to what the Prophet had said to Ali, “May God fight the one who fights you and may God be hostile to the one who is hostile towards you.”
 Al-Kamil fil-Tarikh, 5:42
 Sahih al-Tirmidhi, 2:301; Sahih al-Nisai, 2:271; Sahih b. Majah, p. 12; Abu Nuaym, Hiliyat al-Awiya, 4:185
 Musnad Ahmad b. al-Hanbal, 4:164; Kanz al-Ummal, 6:153
 Musnad Ahmad, 6:52; Al-Imamah wal-Siyasah, 1163; Tarikh al-Tabari, 4:469
 Usud al-Ghabah, 2:154; Al-Isabah, 1:501