The issue of Intercession (Shafa'ah) is one of the most controversial issues within Islam. The Shi'a school of thought and some schools within the Sunni tradition believe in the concept of Intercession, while others, like Wahabism reject it and say that whoever believes in it is not a Muslim, rather is a heretic. The Quran addresses this issue in three manners. First, there are verses which negate intercession, such as 2:123 and 2:254. Second, there are verses which say that the Intercession is exclusively the domain of Allah—He and only He has the ability to intercede, such as in 6:70 and 39:44. Third, there are verses which take precedence over the first two categories and it is in these verses that the power and ability of intercession is best defined. They state that while the Intercession is the absolute right of Allah, nevertheless, if He wishes, He can extend it to certain people among His creation. The Quran states:
According to these verses, certain people will have permission from Allah—such as prophets, imams, and awliya' (intimate friend of Allah)—to intercede and help people by the permission of Allah. Without His permission, no intercession will be accepted. Even during their lifetime, prophets had the ability to intercede on behalf of those who repented and sought forgiveness and returned to the path of Allah. The Quran states:
We sent no messenger but to be obeyed by the leave of Allah. If they who have been unjust to themselves had come to you (Prophet Muhammad) and begged Allah's forgiveness, and the Messenger had begged forgiveness for them—indeed they would have found Allah All-Forgiving, Most Merciful.9
(The brothers of Yusuf) said, “O our father! Ask forgiveness from Allah for our sins. Indeed, we have been sinners.” He said, “I will ask my Lord for forgiveness for you.” Verily, He, and only He, is the Oft-Forgiving, Most Merciful.
The Prophet Muhammad has also mentioned to the people in regards to his own intercession:
My intercession will be for the people who committed the cardinal sins (al-kaba΄ir) except shirk and dhulm (polytheism and oppression).23
Shafa΄ah is not to ask the prophet or the imams for protection or to ward off calamity or to bring happiness and success. Rather, it is to plead to Allah, the Almighty by the sake of those who are near to Him, like the prophets and the imams.
As the Noble Quran asserts, only those who receive promise and permission from Allah can intercede and help people on the Day of Judgment. Intercession will be for those with good intentions and good belief in this life, who neither defied Allah nor challenged His authority but, perhaps fell behind in part of their religious obligations. Their good record will help them receive the intercession of the messengers, the imams, and the believers on the Day of Judgment.
Imam Ja'far al-Sadiq, the sixth Imam of the school of Ahlul Bayt, at the time of his martyrdom called his relatives and companions and said, “Verily, our intercession will never reach one who takes the prayers lightly.”
 Noble Quran, 10:3
 Noble Quran, 2:255
 Noble Quran, 20:109
 Noble Quran, 21:28
 Noble Quran, 19:87
 Noble Quran, 34:23
 Noble Quran, 12:97-98
 al-Muttaqi al-Hindi, Kanz al-Ummal, Hadith 39043
 Ibid., Hadith 39041
 al-Majlisi, Bihar al-Anwar, 82:236