The method adopted by any group to convey the da‘wah must be Shari‘ah Law derived from the seerah of the Messenger of Allah (saw) in his performance during the conveyance of the da‘wah. This is so because it is obligatory to follow him, as Allah (swt) says,
“Surely, in the Messenger of Allah, is the best example for those who believe in Allah and the Last Day and remember Allah often.” [TMQ 33:21]
“Say if you love Allah follow me, Allah will love you and forgive you your sins.”[TMQ 3:31]
“Whatever the Messenger gives you take it, and whatever he forbids you abstain from it.” [TMQ 59:7]
There are many other such ayat which denote that following the Messenger of Allah (saw), taking him as an example and taking all aspects of the deen from him is obligatory.
Since the Muslims nowadays live in dar al-kufr (i.e. a land where the sovereignty is to other than Allah (swt), or the authority is not in the hands of the Muslims, or both), because they are governed with laws other than those of Allah (swt), so their land resembles Makkah where the Messenger of Allah (saw) was first sent as a Messenger. Therefore, it is necessary to take the Makkan part of the Messenger of Allah’s (saw) seerah as an example in conveying the da‘wah.
By studying the life of the Messenger of Allah (saw) in Makkah until he had managed to establish the Islamic State in Madinah, it is evident that he went through clearly defined stages, in each of which he used to perform specific actions. So the Party took from that the method of its work, the stages of its action and the deeds which it has to perform during these stages in accordance with the deeds which the Messenger of Allah (saw) performed during the stages of his work.
Based on the Ijtihad of Sheikh Taqi-ud-Deen An-Nabhani (rh) on the method, he defined the work of a group into three stages:
The First Stage: The stage of culturing to produce people who believe in the idea and the method of the Party working to re-establish the Khilafah, so that they form the solid body of the group.
The second Stage: the stage of interaction with the Umaah, to let the Ummah embrace and carry Islam, so that the Ummah takes it up as her issue, and thus works to establish it in the affairs of life.
The Third Stage: The stage of establishing government, implementing Islam generally and comprehensively, and carrying it as a message to the world.
May Allah (swt) strengthen the sincere da'wah carriers in their continuous work to resume the Islamic way of life. May Allah (swt) grant the Islamic Ummah the help, success and victory, and at that moment the believers will rejoice, Inshallah.