Urwah (may Allah have mercy on him) states concerning Sayyiduna Uthman bin Affan (may Allah be pleased with him) that he stayed behind in Madinah to nurse his wife, the daughter of the Messenger of Allah (peace and blessings be upon him), who was gravely ill, so the Messenger of Allah (peace and blessings be upon him) allotted him a share as well. He said: And will I have the reward too, O Messenger of Allah? He (peace and blessings be upon him) said: "And the reward too."
Hadith Referenceالمعجم الكبير للطبراني / العشرة / 125