Abu Huraira (r.a.) narrates:
They asked Rasulullah (saw) about the state of the children of the polytheists (in the hereafter), whereupon he said:
“Allah knows best how they would have turned out had they not died as children.” (Bukhari, Muslim, Tirmidhi)
Aisha (r.a.) narrates:
“A little child died and I said ‘How happy for him, he is now a sparrow amongst the sparrows of Paradise.’”
Rasulullah (saw) said:
“Do you not know that Allah created both the Paradise and the Hell. Just as He created some for the former, He also created some for the latter!”
According to another narration, he said:
“Allah created some people for Paradise; He determined this while they were still in the spine of their father. Allah also created some people for Hell, and they too were determined for this while still in the chime of their father.” (Muslim – Abu Dawud)
Aisha (r.a.) narrates:
I asked Rasulullah (saw): “O Rasulullah! What is the state of the children of the believers (in the hereafter) who have died as children?”
“They depend on their fathers” he said.
“How can that be, when they have not lived to do anything?” I asked.
“Allah knows the things they would have done had they lived” he said.
“And what about the children of the unbelievers O Rasulullah?” I asked.
“They too are dependent on their fathers” he said.
“Without having done anything?” I asked.
He said: “Allah knows best what they would have done had they lived.” (Abu Dawud)
“We will never cause suffering until We disclose a Rasul with whom We warn!” (Quran 17:15)
Anas (r.a.) narrates:
A man asked: “O Rasulullah! Where is my father?”
Rasulullah (saw) said: “Your father is in Hell.”
After the man left, Rasulullah said: “Your father and my father are both in fire.” (Abu Dawud)
Zaid b. Sabit (r.a.) narrates:
Rasulullah (saw) was on a camel in the garden of the Najjar family when suddenly the camel got frightened and ran away, nearly causing Rasulullah (saw) to fall off. We then realized there were four or six graves in the garden. Rasulullah (saw) said: “Does anybody know who are buried here?”
“I know” said one of the men nearby.
“When did these people die?” asked Rasulullah.
“They died as polytheists in the state of duality” answered the man.
“The ummah (people) of Muhammad will be taken to account in their graves. If I knew you would not refrain from burying your deceased, I would pray to Allah to make you hear the sounds of torment coming from these graves as I am hearing them right now.” (Muslim, Nesei)
Sahl (r.a.) narrates:
A reputable wealthy man, who helped the Muslims, joined Rasulullah (saw) in battle. Looking towards him, Rasulullah (saw) said:
“Whoever wants to see a man of hell should look at this man.”
Upon this, one of us followed this wealthy man, who fought fiercely against the enemies of Islam. Eventually he was injured and to not endure the pain and die quickly he positioned his sword pointing towards his chest and leaned on the sword with all his body until the sword pierced through his chest and thus he committed suicide. The man who had followed him and saw this quickly ran back to Rasulullah (saw) and said: “I witness that you are truly the Rasul of Allah” (i.e. your verdict about this man was accurate).