Sahih Muslim | Book 32 | Hadith Number 6311

Narrated by Abdullah b. Mas'ud
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.