This paper is aimed at describing the importance of speech politeness in the Islamic da'wah. It is known that polite language uttered by a da’i(the one does the da’wah) would harmonizepeople and establish harmony amongst religious communities. The inevitability of pluralism in Indonesia and Qur'anicargument which states that Islam is a mercy for all the creatures promote the need to build a more polite, friendly and peaceful strategy of da’wah. Politeness strategy applied in a da'wahspeech may lead to building acharacter of a wise, polite and smart nation and may help preserve Indonesia’s diversity by keeping social and cultural conflict at bay.