The person who has a need should come to the one he needs [Etiquette]

Zayd b. Thâbit reports that ‘Umar b. Al-Khattâb 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 ‘Umar entered] he moved his head away from her. ‘Umar 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.” ‘Umar replied, “Rather, the need is mine.”

Al-Bukhârî, Al-Adab Al-Mufrad. Shaykh Al-Albânî grades its chain of narration hasan in Sahîh Al-Adab Al-Mufrad Vol. 2 p29.

More:

1. From the Etiquette of a Son with his Father
2. A Visitor looking around the House
3. Going out to Spread Greetings
4. Hospitality and Sharing: How the Salaf Lived
5. Sleeping during the day [best and worst times]
6. Supplicating for an Unbeliever
7. The Recommendation for Men to Smell Pleasant [wearing perfume]