A dayee is an individual who invites others to God and the truth. A madu is the one called to God and the truth. The successful dayee will need to consider many aspects of Islamic knowledge, the condition of the environment he is working in, his resources and means, and what he wishes to accomplish.

The aim of calling man to God is that, while still living in the world, he may become an inhabitant of the hereafter. He will thus discover God’s greatness in the greatness of the world. He will start experiencing heavenly blessings in worldly comforts, while worldly hardships will remind him of the torment of hell fire.

Source: Calling People to God