Jami` at-Tirmidhi Book 10, Hadith 97
The Messenger of Allah said: "Whoever has three that precede him (in death) while they did not reach the age of puberty, then they will be a well-fortified fortress for him against the Fire."
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."
"I heard my grandfather, the father of my mother, Simak bin Al-Walid Al-Hanadi narrating, that he heard Ibn Abbas narrated, that he heard the Messenger of Allah saying: "Whoever has two predecessors (in death) among my Ummah, then Allah will admit them into Paradise."So Aishah said to him: "What about one from your Ummar who has one precessor?" He (pbuh) said: "And whoever has one predecessor O Muwaffaqqah!" So she said: "What about one who does not have a predecessor from your Ummah?" He said: "I am the predecessor for my Ummah: you will never suffer (in grief) for (the loss of) anyone similar to me."