Propagation means conveying a message and since the mission of all divine prophets particularly the holy prophet of Islam (S) was to bring humanity forth from darkness into light, propagation enjoys significant importance as a means to convey God's message to His servants. Propagation methods in Islam can be sorted out into three categories e.g. verbal (oral), written and practical each having various types. The verbal method includes speeches, lamentations, debates and commanding the good and forbidding the bad and so on. The written method includes letters, written invitation etc. As for the practical method, it has different types which will be covered in our detailed answer.
Propagation means conveying a message using suitable and effective tools. Throughout history all schools of thought and people trying to deliver their message to others have used different methods and tools. In today's world extensive propagation is carried out by various schools to attract people to different thoughts and beliefs and the leaders of those schools are trying to familiarize people with their opinions and beliefs and to recruit new followers using suitable propagation tools and techniques.
Since the mission of Islam as the last and the most perfect religion is an eternal and a global mission, propagation and acquainting people with divine law and knowledge as well as giving good tidings and warning people are of high importance. That is because Islam is the religion of guidance and it has considered guidance to be of paramount importance. It is, therefore, impossible to guide people unless they are familiar with the goals, knowledge and teachings of Islam.
Propagation methods in Islam can be classed under three categories namely verbal propagation, written propagation and practical propagation:
1-Verbal propagation: This method is very diverse and includes speeches, sermons, call to prayer, supplications, reciting the luminous verses of the holy Quran, holding celebration programs on various auspicious occasions and mourning on grievous occasions, debates, commanding the good and forbidding the bad etc.
2-Written propagation through:
a) Verses of the Holy Quran:
The luminous verses of the holy Quran as a written work, which has always been available to all humans, have an outstanding value in guiding humans in a way such that their guiding role even in the present time leaves no room for any doubt. As it says: "There has come to you light and a clear Book from Allah; With it Allah guides him who will follow His pleasure into the ways of safety and brings them out of utter darkness into light by His will and guides them to the right path."
b) Valuable traditions narrated from the holy Prophet (S) and his household (A.S).
c) Sending letters:
Sending letters had been considered by the holy prophet (S) since the early days of his invitation. His letter to Najashi, the king of Ethiopia, is an instance of this propagation method. Following the Hudaibiya peace treaty and when he was assured that pagans would not invade again, the holy prophet (S) implemented his idea of propagation beyond Hijaz and calling everyone to monotheism and the religion of Islam by sending envoys and letters far and wide. This invitation lasted up until his demise. Great kings, Christian religious authorities and chiefs of famous tribes were the primary addressees of these letters.
3-Practical propagation: Islam has greatly emphasized this method. The holy Quran states: "What! Do you enjoin men to be good and neglect your own souls." Elsewhere it says: "O you who believe! Why do you say that which you do not do?"
Imam Sadiq (A) said: “Call people to righteousness through means other than your tongues”. The holy Prophet (S) and Imams (A.S) have largely benefitted from this method to propagate and promulgate Islam because the words of a propagator have an influence on others only when he himself puts them to practice. . Also the holy Prophet (S) and Imams' (A.S) capability of miraculous and extraordinary acts which other people are unable to perform is another type of practical propagation which has been tremendously effective in people's tendency toward Islam.
In addition, Islam has considered subtle points and various conditions for propagation following which will have a remarkable impact on permeation and fruition of propagation efforts and eventually promotion of Islam. Some of these factors are:
1-The importance of the place of propagation:
Preaching religious issues and delivering God's commands to people will be more effective if carried out in suitable places. The holy Prophet of Islam (S) delivered God's message and called people to Islam during Hajj pilgrimage to Mecca.
Prior to his trip to Karbala, Imam Hussein (A.S) stayed in Mecca for a few months waiting for pilgrims to come in order to explain his mission and to inform pilgrims of Yazid's crimes so that each pilgrim would convey the Imam's (A.S) message to people in his own region. Later, Imam Hussein (A.S) left Mecca for Kufa and Karbala.
Imam Sadiq (A.S) would stand among numerous pilgrims in Arafat dessert turning his face to four directions reciting three times at each direction "O people! Your leader was the holy Prophet (S) and after him he was Ali bin Abi Taleb (A.S) then Hassan (A.S) and Hussein (A.S) then Ali bin Hussein (A.S) then Muhammad bin Ali (A.S) and now it is me."
Places such as Mecca and mosques are ideal for propagation. Throughout history mosques and minbars have been together with each other. The holy Prophet (S) said: "Any group who gathers in any of God's mosques to recite the Book of Godand to study it among themselves, serenity will descend on them and they will be encompassed with God's compassion."
2-Time of propagation:
Proper timing of propagation is one of the factors influencing the propagator's success. If we take a glimpse at the verses of the holy Quran and the infallibles' supplications, we will come to understand the important role of timing in actions especially in propagational encounters. God Almighty has revealed the holy Quran on Qadr (grand) night. "Surely we revealed it on the grand night." Choosing this time to reveal the holy Quran adds to its importance because the "Qadr" night falls in the best time i.e. the holy month of Ramadan. Three years following the prophetic mission of Prophet Muhammad (S), this verse was revealed: "Therefore declare openly what you are bidden and turn aside from the polytheists."
The revelation of this verse after three years indicates that before this time, suitable ground and conditions for open invitation to the religion of God and detachment from pagans and polytheists were missing.
While the pagans of Quraysh prevented the holy Prophet (S) from propagating Islam , he would make use of the forbidden months going to bazaars such as "Akaz","Mejna " and "Zil Majaz ", standing on a higher place and calling people to the religion of Islam because according to pagans' beliefs fighting and war were forbidden in these months, so he would be safe.
3-Starting in the Name of God: Since the one who is effective in every matter is God and success in every action depends on His will therefore every speech should be started in His name so that the speech receives divine support and leaves a positive impact on people.
The first command the holy Prophet (S) received from God was to start his message and speech in God's name: "Read in the name of your Lord Who created."
4-Connection to divine revelation: Human's speech is never free from errors unless it is connected to divine revelation. A propagator should resort to what God Almighty has revealed to His holy Messenger (S) which is the right path otherwise there is a danger of going astray "Therefore hold fast to that which has been revealed to you; surely you are on the right path."
The holy Prophet's (S) words and propagation that are connected to the source of revelation are free from whims and desires: "Nor does he speak out of desire it is naught but revelation that is revealed." This is one of the secrets why his words and propagation were effective.
4-Making use of well-established and logical arguments and avoiding baseless, flimsy and undocumented points that are opposed to moral and human standards:
The holy Quran has put forth issues with arguments and reasoning and has commanded its followers to use the best form of polemics and states that:"And do not abuse those whom they call upon besides Allah." It even asks its opponents to provide reasons for their claims and states that:"[O Prophet] Say: Bring your proof if you are truthful."
It also says: "Say: Bring your proof [for your wrong claims]; then they shall know that the truth is Allah's".
5-Good tidings and encouragement:
The Holy Quran has given numerous good tidings to call people to almsgiving: "The parable of those who spend their property in the way of Allah is as the parable of a grain growing seven ears (with) a hundred grains in every ear; and Allah multiplies for whom He pleases."
Elsewhere to encourage people to perform good deeds and prayers it says:"Surely they who believe and do good deeds and keep up prayer and pay the poor-rate they shall have their reward from their Lord, and they shall have no fear, nor shall they grieve."
The holy Quran persuades people to perform good deeds and warns against evil deeds.
One of the the holy Prophet’s most important acts of guidance was to forbid people from worshipping their whims or following their carnal desires. In many verses pagans and sinners have been warned with promises of severe chastisement. It says:"Surely they who disbelieve in the communications of Allah shall have a severe chastisement; and Allah is Mighty, the Lord of retribution".
7-Avoiding fear in propagation of religious teachings:
The holy Quran has encouraged sincere propagators who do not fear anyone but God in their propagation and says:"Those who deliver the messages of Allah and fear Him, and do not fear any one but Allah; and Allah is sufficient to take account."
These subtle points and their application by infallible leaders (A.S) and their true followers have led to rapid growth and expansion of Islam.
 Quran 3:15,16
 Tabari, Ibn Jarid, Tabari History, vol.2 p.882, Tahqiq Nukhbatun minal Ulama al-Ajella, al-A'lami Institute, Beirut
 Quran 2:44
 Quran 61:2
 Bihar al-Anwar, vol.5, p.198 Harun narrated from Ibn Sadaqa from Abi Abdallah PBUH who said: "Call people [to Islam and good deeds] by your deeds and do not call them with your words."
 Kulayni, Muhammad ibn Yaqub, Forou'e Kafi, vol.4, p.466, Dar al-Kutub al-Islamiya, Tehran
 Nouri Tabarsi, Haj Mirza Hussein, Mustadrak al-Wasa'il, vol.3, p.363, Islamyia Publishing Company
 Quran 97:1
 Quran 15:94
 Ayatollah Subhani, Jafar, Forouhge Abadiiat, vol.1, p.326, Hadaf publications, 1982
 Quran 96:1
 Quran 43:43
 Quran 53:3,4
 The holy Quran 16:125 Call to the way of your Lord with wisdom and goodly exhortation, and have disputations with them in the best manner;
 Quran 6:108
 Quran 2:111
 Quran 28:75
 Quran 2:261
 Quran 2:277
 Quran 3:4
 Quran 33:39