Mishkat al-Masabih #1643

Abu Huraira reported God’s messenger as saying, “No Muslim will suffer the death of three sons and go to hell, except to expiate the oath.”(Cf. Qur'an, xix, 71, which says everyone shall go down to it, and that this is a decree from God which must be accomplished. The meaning of the tradition is said to be that such people will go for a very brief time which will be enough to make this decree no longer applicable to them. The decree is treated as equivalent to an oath) (Bukharl and Muslim.)