All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
First of all, we ask Allaah to enable you to do good and guide you and grant you success in this good work. Indeed, building mosques and calling to Allaah are some of the greatest acts of worship. Ibn Abbaas narrated that the Prophet said, “Whoever builds a mosque for the sake of Allaah, even if it were like a sparrow’s nest for its eggs, Allaah will build for him a house in Paradise.” [Ahmad]
With regard to calling people to Allaah, Allaah says (what means): {And who is better in speech than one who invites to Allaah and does righteousness and says: Indeed, I am of the Muslims.} [Quran 41:33]
At-Tabari, in his Tafseer, quoted the statement of Al-Hasan Al-Basri in which he recited this verse and then said, “This is the beloved person by Allaah, the Wali (ally) of Allaah, the elite of Allaah, the best of people to Allaah, the most beloved creation to Allaah, he answered the call of Allaah in what Allaah called him to do and called the people to do what Allaah called him to do, and he did righteous deeds in responding to the call of Allaah and then said, ‘I am a Muslim;’ this is the vicegerent (Khaleefah) of Allaah.”
We recommend you to do several matters in order to make your mission successful, among which are the following:
1- We advise you to fear Allaah. Fearing Allaah leads to getting all matters made easy by Allaah, and Allaah will repel all plots and evil from you; Allaah says (what means): {And whoever fears Allaah - He will make for him a way out.} [Quran 65:2] Allaah says (what means): {And whoever fears Allaah - He will make for him of his matter ease.} [Quran 65:4]
2- Realize that the profession of calling to Allaah is similar in part to the medical profession; a doctor is merciful to his patients and is keen on doing what benefits them, and so is a caller to Allaah. The Prophet indeed used to be merciful and keen on what benefits the people. Allaah says (what means): {There has certainly come to you a Messenger from among yourselves. Grievous to him is what you suffer; [he is] concerned over you and to the believers is kind and merciful.} [Quran 9:128] Besides, Jaabir narrated that the Prophet said, “My example and your example is that of a person who lit the fire, and insects and moths began to fall into it, and he would be making efforts to take them out, and I am holding you back from fire, but you are slipping from my hand.” [Muslim]
3- A caller to Allaah should know what he is calling the people to, so he speaks of what he knows and does not indulge in what he does not know. He speaks with a good and acceptable style without slander or any provocation such as insulting and so forth. ‘Abdullaah ibn ‘Amr narrated that the Prophet said, “Convey from me even if it were only one verse.” [Al-Bukhari] Also, a caller to Allaah should refrain from speaking about what he ignores. If he is asked about what he does not know, then he should say, ‘I do not know’; and this is half of knowledge. He should beware of speaking about the religion of Allaah without knowledge. Allaah says (what means): {And do not pursue that of which you have no knowledge. Indeed, the hearing, the sight and the heart - about all those [one] will be questioned.} [Quran 17:36] Speaking about Allaah without knowledge is mentioned after the mention of Shirk in the Quran (to show its seriousness); Allaah says (what means): {Say: My Lord has only forbidden immoralities - what is apparent of them and what is concealed - and sin, and oppression without right, and that you associate with Allaah that for which He has not sent down authority, and that you say about Allaah that which you do not know.} [Quran 7:33]
4- Patience. The road of calling people to Allaah is long, and the devil may try to break one’s motivation. Allaah says (what means): {[Satan] said, "Because You have put me in error, I will surely sit in wait for them on Your straight path.} [Quran 7:16] A Muslim should also remember that he is on the path that the Prophets and reformers of this nation trod and that he is their companion on this path; and how great indeed is their company. Also, the devils from among the human beings may stand in the way of his call, and they would harm him and repel people away from him. So he should continue in his path and not pay any attention to them, as the Prophet did with his people; rather, he should supplicate Allaah to guide them. ‘Abdullaah ibn Mas'ood said, “I have definitely heard the Prophet relate the story of a Prophet who had been beaten by his people and was wiping the blood from his face and said, ‘My Lord, forgive my people, for they do not know.’” [Al-Bukhari and Muslim]
5- It is very important to vary the methods of calling to Allaah so that the mosque would attract the worshipers, especially the young people. You should take their needs into account and use modern means when doing Da’wah (proselytization).
6- Being concerned about the worshipers in the mosque and its neighbors, ask about all of them, and provide help to those who need it. It is in this manner that you will earn the hearts of the people, and this is the best way to influence them. Anas narrated:
“There was a Jewish boy who used to serve the Prophet . Once, the boy became sick, so the Prophet went to visit him. He [the Prophet] sat beside his head and said to him, ‘Embrace Islam.’ The boy looked at his father, and the latter said to him, ‘Obey Abul-Qaasim.’ [Abul Qaasim was the nickname of the Prophet .] So the boy became Muslim, and the Prophet came out saying, ‘Praise be to Allaah who saved him from the Fire.’” [Al-Bukhari]
Finally, we emphasize our advice that you should earnestly seek Islamic knowledge and become well-grounded in the religion. For more benefit, please refer to fataawa 12803, 26112, 173411 and 85658.
Allaah knows best.