Proofs from the Holy Qur'an and the Prophetic Sunnah stress the obligation of Da`wah to Allah (Exalted be He) in Islam. There are many proofs of this obligation. Allah (Glorified be He) says: Let there arise out of you a group of people inviting to all that is good (Islâm), enjoining AlMa'rûf (i.e. Islâmic Monotheism and all that Islâm orders one to do) and forbidding AlMunkar (polytheism and disbelief and all that Islâm has forbidden). And it is they who are the successful. Allah (may He be Praised) says: Invite (mankind, O Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭ ﺳﻠﻢ) to the Way of your Lord (i.e. Islâm) with wisdom (i.e. with the Divine Revelation and the Qur'ân) and fair preaching, and argue with them in a way that is better. Allah (Exalted be He) says: and invite (men) to (believe in) your Lord and be not of AlMushrikûn (those who associate partners with Allâh, e.g. polytheists, pagans, idolaters, and those who disbelieve in the Oneness of Allâh and deny the Prophethood of Messenger Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭ ﺳﻠﻢ). Allah (may He be Praised) also says: 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, I and whosoever follows me (also must invite others to Allâh i.e. to the Oneness of Allâh Islâmic Monotheism with sure knowledge).
Allah (may He be Praised) explains that the followers of the Prophet (peace be upon him) are those who call to Allah and that they are the people with insight. As known, it is obligatory to follow the Prophet (peace be upon him) and act upon his religion, as Allah (Glorified be He) says: Indeed in the Messenger of Allâh (Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭ ﺳﻠﻢ) you have a good example to follow for him who hopes for (the Meeting with) Allâh and the Last Day, and remembers Allâh much.
Scholars say that Da`wah to Allah (Glorified be He) is a collective obligation in the countries where preachers perform this task. This is because every country needs some people to carry out the mission of Da`wah to Allah. It is a collective obligation in the sense that if some carry out this obligation, the others are not sinful and it becomes a stressed Sunnah and a righteous deed that they can perform.
If all the people of a particular country do not fulfill such an obligation perfectly, they become sinful and it becomes obligatory for everybody to fulfill it according to the capability and possibility of each. In general, there should be a group of people
to carry out the task of Da`wah to Allah (Glorified be He) all over the world, conveying the Message of Allah and showing Allah's Ordinances with every possible means. This is because the Prophet (may peace be upon him) sent messengers to kings and rulers with messages, calling them to Allah (Exalted be He).
Nowadays Allah (Glorified be He) has made Da`wah easier as new methods of Da`wah have arisen. There are now many different approaches to Da`wah to Allah, thus leaving no excuse to people. These means include the radio, the television, the press and others. Thus, it is obligatory for knowledgeable and righteous people and the followers of the Prophet (peace be upon him) to fulfill such an obligation. They should support one another to convey the Message of Allah to mankind, fearing nobody for the sake of Allah. They should not favor anyone, young or old, rich or poor; rather, they have to convey Allah's Ordinances to humanity in the same way that such ordinances were revealed to the Prophet (peace be upon him).
This mission may be an individual obligation if there is none to enjoin what is good and forbid what is wrong. This is because enjoining what is good and forbidding what is wrong is both an individual and a collective obligation. If you are in a place where none fulfill such an obligation or convey Allah's Ordinances except you, it is obligatory for you to fulfill it. If there are some people who carry out the mission of Da`wah, convey Allah's Message, enjoin what is good and forbid what is wrong other than you, it becomes a supererogatory act for you. If you continue fulfilling such an obligation, you will become among those who compete with one another in doing righteous deeds.
The evidence of being a collective obligation is Allah's Saying: Let there arise out of you a group of people inviting to all that is good (Islâm) Commenting on this Ayah, AlHafiz Ibn Kathir and some scholars said Allah (may He be Praised) orders mankind to appoint a group from among them to carry out the mission of Da`wah to Allah, propagate His religion, and convey His Message.
It is wellknown that Allah's Messenger (peace be upon him) invited people to Allah. He called the people of Makkah to Allah as possible as he could. Similarly, the Prophet's Companions (may Allah be pleased with them) did the same
as possible as they could. When they migrated, they expanded the range of Da`wah to Allah. Then, when they traveled to different countries all over the world after the death of the Prophet (peace be upon him), they (may Allah be pleased with them) carried out Da`wah to Allah according to capacity and religious knowledge of each of them. When preachers are few and sins and ignorance are rampant, Da`wah to Allah becomes an individual obligation, each according to his capacity. If someone is carrying out the mission of Da`wah in a village, a small town, etc., it becomes sufficient and the mission becomes a supererogatory act for others.
As for the other parts of the world and other people, both scholars and rulers have to make Da`wah to Allah and convey Allah's Commands, each according to his capacity. This is an individual obligation for each of them.