Five Prostrations for glad tidings

Ja'far ibn Muhammad (A.S.) said that:
Once when the Prophet, peace be upon him and his progeny, was travelling, he dismounted and then performed five prostrations (Sijdah). When he mounted again, one of his companions said: "We saw you do something, O messenger of Allah, which you never did before." He said: "Yes, Jibraeel came to me and gave me glad news that ‘Ali belongs in Paradise. So I went into prostration to thank Allah.
When I raised my head, he said: 'Fatimah belongs in Paradise.' I went to prostrate again to thank Allah. And when I raised my head, he said: 'al-Hasan and al-Husayn are the masters of the youths of Paradise.' So I prostrated to thank Allah. And when I raised my head, he said: 'And those who love them belong in Paradise.' So I prostrated to thank Allah. And when I raised my head, he said: 'And those who love the people who love them (Ahlul Bayt) belong in Paradise.' (So I prostrated to thank Allah)."