Answered by Sayyidi Habib Umar bin Hafiz (may Allah protect him and benefit us by him)
What is the difference between the ‘Greatest Intercession’ and the intercession of Allah’s chosen slaves?
The ‘Greatest Intercession’ is specific to the Prophet Muhammad ﷺ. It is also known as the ‘Praiseworthy Station’ (al-Maqam al-Mahmud). It takes place when the Prophet intercedes on behalf of all people that they be moved from being exposed to the sun to the place where the judgement will take place. Everyone, whether they are believers or non-believers, will benefit from this intercession.
After that comes the intercession of the various prophets. Each prophet has a greater right than anyone else to intercede for his own nation, and he may be given the permission to intercede for people not from his nation according to his station with Allah and his relationship to those people. After that comes the intercession of the people of extreme truthfulness (al-siddiqun) and the scholars, then the intercession of the martyrs and the pious. Some believers will be given permission to intercede for themselves; others will be given permission to intercede for two or three people; others will be given permission to intercede for a group of people. Each person is given this permission according to his rank with Allah. The Prophet ﷺ said that Uways al-Qarani will be given permission to intercede for people as numerous as the Arab tribes of Rabi`a and Mudar, which amounts to millions of people.