Hadith No: 1
Al-Muttaqi al-Hindi - Kanz al-'Ummal fi Sunan al-Aqwal wal-Af'al
Volume: (11) - Page Number: (573)
32713 - "Do not curse Abu Bakr and Umar, for they are the masters of the elders of the people of Paradise from the first and the last, except for the prophets and messengers. And do not curse Hasan and Husayn, for they are the masters of the youth of the people of Paradise from the first and the last.
And do not curse Ali, for whoever curses Ali has cursed me, and whoever curses me has cursed God, and whoever curses God, God will punish him."