The Book of Virtue, Good Manners and Joining of the Ties of Relationship (Kitab Al-Birr was-Salat-I-wa'l-Adab)
Muslim :: Book 32 : Hadith 6311
Abdullah b. Mas'ud reported Allah's Messenger (may peace be upon him) as saying: Whom do you count as" Raqub" amongst you? They (his Companions) said: One who has no children (the children are born unto him but they do not survive). Thereupon he (the Holy Prophet) said: He is not a Raqub but Raqub is one who does not find his child as the forerunner (in Paradise). He then said: Whom do you count as a wrestler amongst you? We said: He who wrestles with persons. He said: No, it is not he but one who controls himself when in a fit of rage.