Zayd b. Thābit reports that ʿUmar b. Al-Khattāb came to him one day seeking permission to see him. He permitted him to enter, and at the time his head was in the hands of his slave-girl, who was combing his hair. [When ʿUmar entered] he moved his head away from her. ʿUmar said, “Let her continue combing your hair.” [Zayd] said, “O Leader of the Believers! If only you had sent for me, I would have come to you.” ʿUmar replied, “Rather, the need is mine.”
Al-Bukhārī, Al-Adab Al-Mufrad. Shaykh Al-Albānī grades its chain of narration hasan in Sahīh Al-Adab Al-Mufrad Vol. 2 p29.