Musnad Abu Ya'la al-Mawsili 152:94

On the authority of Ibrahim, from al-Harith ibn Suwayd, from Abdullah, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Who do you consider to be the *raqūb* (childless) among you?" We said: "The one who has no children." He said: "That is not the *raqūb*, but the *raqūb* is the one who has not sent forth anything of his children [i.e., who has not had any children die before him to intercede for him]." He said: "And who do you consider to be the *ṣuraʿah* (strong wrestler) among you?" We said: "The one whom men cannot throw down." He said: "That is not it, but it is the one who controls himself at the time of anger."