Da‘wa through excellent customer service is actually how Yemeni muslim traders spread Islam to Indonesia, East Africa, and parts of India. They ran small shops, engaged in trade, maintained good relations with local people, and demonstrated good manners. They would often give more than was due in their transactions with customers. This behaviour led people to warm to them and eventually ask questions about Islam as a way of life.

Al-Akhlāqu Al-Muḥammadiyyah.