Allah has blessed us with the ability to speak. He gave us this ability so that we may communicate with one another, express our feelings and reveal our intentions. The tongue is a great endowment of Allah, which may be used to praise and thank Him for which one earns reward.
The Quran says: “Whose speech can be better than the one who calls to Allah and acts righteously and says fearlessly ‘I am a Muslim.’ Good and evil cannot be alike, replace evil with that which Is better and if there was enmity between you and the other he will become a dearest friend. Though only the patient will achieve this those who are truly fortunate. If Satan tempts you then seek Allah’s protection. He is the Listening and the Knowing” (Ha Meem Sajda: 33-36).
This, in the first instance that refers to the Messenger (peace be upon him), to the disciples who were scholars of the Quran, the caller of the Azan, the preachers who teach and warn people. The conditions attached to this calling demand that the caller practice what he preaches. So, these people call to Allah with the Quran sincerely with no worldly motivation.