It is narrated from Sayyiduna Abu Rafi' (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said to Sayyiduna Ali (may Allah be pleased with him): "Indeed, the first four people to enter Paradise will be I, you, Hasan and Husayn. Our offspring will be behind us, our wives will be behind our offspring, and our followers will be on our right and on our left."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2611