Jami` at-Tirmidhi 1061
جامع الترمذي#1061Da'ifAbdullah bin Mas'ud narrated that: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
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirDaif
Al-AlbaniDaif
Zubair Ali ZaiDaif
In-book reference: 10:97