It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "The example of the believer is like that of the perfume seller: if you sit with him, he benefits you; if you walk with him, he benefits you; and if you become his partner, he benefits you."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13484