Abdullah bin Umar (may Allah be pleased with them both) said: There were two crippled people in Makkah, and they had a son who would carry them in the morning, bring them to the mosque and seat them there, then he would go and earn a living. When evening came, he would carry them and take them back. One day the Messenger of Allah (peace and blessings be upon him) did not find him, so he (peace and blessings be upon him) asked about him, and they said: He has died. The Messenger of Allah (peace and blessings be upon him) said: "If anyone were spared for the sake of anyone, the son of the two crippled ones would have been spared." Thereafter he (peace and blessings be upon him) often used to say this.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 7131