The famous Muhaddith (Hadith-expert) Imam Tabarani has related in Mo'jam Ausat on his own authority, using his own chain of transmission from Hadhrat Abdullah bin Abbas (May Allah SWT be well pleased with him) and Imam Ali Muttaqi Hindi has recorded this Hadith in
(Kanzul 'Ummal Vol 13, Pg no. 103/104)
on the authority of Ibn Asaker. The Hadith in Mo'jam Ausat of Imam Tabarani Hadith No. 6649 is being mentioned here.
Translation: "It has been narrated on the authority of Hadhrat Abdullah bin Abbas (May Allah SWT be well pleased with him) that the Holy Prophet (Sallallahu alaihi wa sallam) offered the Salaat (namaaz) of 'Asr. When the Holy Prophet (Sallallahu alaihi wa sallam) was in the 4th raka'at, Hasan and Hussain (May Allah SWT be well pleased with them). So much so that they climbed on the blessed back of the Holy Prophet (Sallallahu alaihi wa sallam).
The Holy Prophet (Sallallahu alaihi wa sallam) seated them in front of Him. Hadhrat Hasan (May Allah SWT be well pleased with him) came forward. The Holy Prophet (Sallallahu alaihi wa sallam) lifted him on His right shoulder and lifted Imam Hussain (May Allah SWT be well pleased with him) on His left shoulder. Then He said, "O people! Shall I tell you who are they whose maternal grandfather and grandmother are better than the whole world? Shall I tell you who are they whose paternal uncle and aunt are better than everybody's paternal uncle and aunt? Shall I tell you who are they whose maternal uncle and aunt are better than everybody's maternal uncle and aunt? Shall I tell you who are they whose mother and father are better than everybody's mother and father? Listen! They are Hasan and Hussain (May Allah SWT be well pleased with him). Their maternal grandfather is the Prophet of Allah (Sallallahu alaihi wa sallam); their maternal grandmother is Hadhrat Khadija (May Allah SWT be well pleased with her); their mother is Hadhrat Fatima (May Allah SWT be well pleased with her); their father is Hadhrat Ali bin Abi Talib (May Allah SWT be well pleased with him); their paternal uncle is Ja'afar bin Abi Talib (May Allah SWT be well pleased with him); their paternal aunt is Hadhrat Umme Hani bint Abi Talib (May Allah SWT be well pleased with her); their maternal uncle is Hadhrat Qasim, the son of the Prophet of Allah (Sallallahu alaihi wa sallam); their maternal aunts are Zainab, Ruqaiya, Umme Kulthoom (May Allah SWT be well pleased with them).
Their maternal grandfather is in heaven; their father is in heaven, their maternal grandmother is in heaven; their mother is in heaven; their paternal uncle is in heaven; their maternal aunts are in heaven and their sister is in heaven and whoever loves them will also be in heaven."