The soul that is not active will stagnate. One of the most important fields in which one can be active is the field of da'wah, calling others to Allaah. This is the work of the Prophets, work which will save you from punishment, realize your potential and enable you to achieve great things. "Now then, for that (reason), call (them to the Faith), and stand steadfast as you are commanded…" [al-Shoora 42:15 – interpretation of the meaning]. It is not true to say that someone is neither making progress nor slipping back (for if you are not making progress, you are therefore falling back – no one is static). If a person is not occupied in acts of worship and obedience, he will be busy with sin and disobedience, and faith can wax and wane (it does not remain constant).

Calling to the correct methodology – by devoting time to it, making mental and physical efforts, and speaking out, so that da'wah becomes the main concern of the Muslim – will block the Shaytaan's efforts to tempt him and lead him astray.

In addition to that, being challenged by obstacles and stubborn people on the journey of da'wah will make the da'iyah stronger in
faith.

Besides bringing a great reward, da'wah is also a means of being steadfast in one's faith and protecting oneself from backsliding,
because the one who is attacking does not need to defend himself, and Allaah is with the da'iyahs, making them stand firm. The da'iyah is like a doctor fighting illness with his experience and knowledge: by fighting the illness in others he will be the least likely to
suffer it himself.