Jami` at-Tirmidhi Book 10, Hadith 95
"I arrived in Al-Madinah and while I was sitting with Umar bin Al-Khattab they passed by with a funeral, over (a person) whom they were praising with good. Umar said: 'Granted.' I said to Umar: 'What is granted?' He said: 'I said as the Messenger of Allah said: "There is no Muslim about whom three bear witness, except that he is granted Paradise." He said: "And two (as well)." He said: 'We did not ask the Messenger of Allah about one.'"
"A funeral (procession) passed by the Messenger of Allah and they were praising him with good statements. So the Messenger of Allah said: 'Granted.' Then he said: 'You are Allah's witnesses on the earth.'"
The Messenger of Allah said: "Any Muslim who has lost three of his children will not be touched by the Fire, except for what will fulfill the oath."