Is it permissible for the preacher to take his call to the people as a means of earning his livelihood?

It is not permissible for a preacher to intend to earn a living or to use da'wah (preaching) as a means to worldly gain, as this is of the category of desiring worldly things through actions meant for the Hereafter. This nullifies the deed, and its doer is warned of the Fire. Among the requisites for a preacher's sincerity are devotion to Allah the Almighty and not seeking any worldly purpose. Indeed, the prophets did not ask for any wage for their call, as mentioned in the Qur'an. However, for someone whose intention in their da'wah is to draw closer to Allah, and who receives a salary or wage from the state or endowments as a consequence and not as an intention, there is no harm in that, and it is not considered earning a living from da'wah.