Sahih Muslim Book 32, Hadith Number 6370.
Chapter : The merit of one who resigns himself to the will of God calmly at the time of the death of one’s son.
Abu Hassan reported: I said to Abu Huraira that my two children had died. Would you narrate to me anything from Allah’s Messenger (may peace be upon him) a hadith which would soothe our hearts in our bereavements? He said: Yes. Small children are the fowls of Paradise. If one of them meets his father (or he said his parents) he would take hold of his cloth, or he said with his hand as I take hold of the hem of your cloth (with my hand). And he (the child) would not take off (his hand) from it until Allah causes his father to enter Paradise. This hadith has been narrated on the authority of Tamim with the same chain of transmitters. And he is reported to have said: Did you hear from Allah’s Messenger (may peace be upon him) anything which may soothe our heart in our bereavements? He said: Yes.