Mu'adhins (callers to prayer) are also included in the people referred to in this verse; they call people to Allah in public, testifying that Allah is the Greatest and the One and Only God, and that Muhammad (peace be upon him) is His Messenger.
Many authentic Hadiths assert the significance and merits of Da`wah, including, When the Prophet (peace be upon him) sent `Aly ibn Abu Talib (may Allah be pleased with him)
to Khaybar he (peace be upon him) told him, 'Call them to Islam and inform them of their duties towards Allah, which Islam prescribes for them, for by Allah, if Allah guides even one person through you, that is better for you than (possessing a great number of) red camels.' (Agreed upon by AlBukhari and Muslim on the authority of Sahl ibn Sa`d may Allah be pleased with him)
In this honorable Hadith, the Prophet (peace be upon him) swore, although he was truthful even if he did not swear, that guiding one man at the hands of `Aly (may Allah be pleased with him) is better for him than possessing a great number of red camels. This denotes that Da`wah is very significant and has a high status.
In addition, this Hadith clarifies that the aim of Da`wah and Jihad (fighting in the Cause of Allah) is not killing people or taking away their property. Their aim is to guide people, save them from their falsehood, and bring them from darkness into the light and from the trap of deviation and the abyss of depravity into the glory of guidance and honor of piety.
guiding one man on the right path is better than possessing a great number of red camels. Hence, guiding a disbeliever (to Islam) brings great benefits and significant gains. Some Muslim scholars asserted that this matter is better than the whole world and whatever is in it.
A place in Paradise equal to the size of a lash is better than the whole world and whatever is in it
One who guides to something good has a reward similar to that of its doer. (Related by Muslim in his Sahih Book of Hadith)
The mentioned above Hadiths and many others that reveal the same meaning urge Muslims to adhere to Da`wah and show its significance and high status in Islam; it is the job of all Messengers (peace be upon them all).
Say (O Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭ ﺳﻠﻢ): "This is my way; I invite unto Allâh (i.e. to the Oneness of Allâh Islâmic Monotheism) with sure knowledge
O you who believe! Be afraid of Allâh, and be with those who are true (in words and deeds).
and be patient. Surely, Allâh is with those who are AsSâbirûn (the patient).
And We made from among them (Children of Israel), leaders, giving guidance under Our Command, when they were patient and used to believe with certainty in Our Ayât (proofs, evidence, verses, lessons, signs, revelations, etc.).