Are the methods of da'wah (calling to Islam) divinely inspired or based on independent legal reasoning? And what is the criterion for them?

The questioner : In the name of Allah, the Most Gracious, the Most Merciful. And may prayers and peace be upon the noblest of the prophets and messengers, our master and our Prophet Muhammad, and upon his family and all his Companions. As for what follows:
His EminenceThe Shaykh- May Allah preserve you - he says:The questioner: Are the methods of da'wah (calling to Islam) divinely inspired or based on independent legal reasoning? And what is the criterion for them? Give us examples of this, and may Allah reward you with good.

The Shaykh: In the name of Allah, and may prayers and peace be upon the Messenger of Allah, and upon his family and his Companions, and those who follow them in faith. As for what follows:
I have mentioned in my previous speech a path that can be relied upon in answering this question, which is his saying - may the prayers and peace of Allah be upon him - : . There is no doubt that the Prophet - may Allah's prayers and peace be upon him and his family - came to us with a complete Shari'ah (Islamic sacred law) that does not need anyone to add anything to it. However, it can be said that the completeness of the Shari'ah lies not in its details and the intricacies of its rulings, but in its rules and its principles. As for the first, and the rules that have been established in the Shari'ah, it is difficult for a researcher to exercise independent legal reasoning in the sphere of derivation and to bring forth some matters that were not known in the early period. I spoke recently in ... this blessed gathering - if Allah wills - about what is called by scholars "unrestricted public benefit" (maslahah mursalah). These unrestricted public benefits are matters that occurred after the Prophet - may Allah's prayers and peace be upon him and his family - that were not known in that first, unique early period, but rather occurred later. Do these new matters fall under the generality of what I mentioned in the previous session after the 'Asr (afternoon) prayer, which is his saying - may Allah's prayers and peace be upon him - : ; meaning: it is possible that some of these new matters can be adopted and acted upon even if they were not previously known or established. This point is, in fact, one of the intricacies of fiqh (Islamic jurisprudence) and the principles of religious innovation (bid'ah). The known principles mentioned by scholars and students of knowledge are only two: the principles of hadith and the principles of the science of fiqh. However, some of the later scholars, relying on a new example in the principles of religious innovation, authored a small treatise titled "The Principles of Religious Innovations."
The truth - I say the truth - is that mastering this science ... helps the jurist to distinguish between what is a misguided religious innovation falling under the generality of that noble Prophetic text, and what is from the unrestricted public benefits for which many scholars, and at their head the Shaykh al-Islam Ibn Taymiyyah - may Allah have mercy on him - call for action. Due to the precision of the matter and the possibility that this new occurrence may be mixed, being either a misguided religious innovation or an unrestricted public benefit, here lies the extreme precision. Ibn Taymiyyah - may Allah have mercy on him - elaborated on this so that the researcher would be clear about the matter. He says - may Allah have mercy on him - : When a new occurrence happens, one looks at the motive for its introduction. If the motive for it was present in the time of the Prophet - may Allah's prayers and peace be upon him and his family - and the Prophet - may Allah's prayers and peace be upon him and his family - did not adopt such a new matter, despite the presence of the requirement for adopting it or for ... its legislation; as long as the requirement was present in his time - may Allah's prayers and peace be upon him and his family - and he did not adopt what was required of it; that is evidence that adopting it when it is found is a misguided religious innovation falling under the generality of his saying - may the prayers and peace of Allah be upon him - : .
One of the clear and evident examples of this is the adhan (call to prayer) for the two 'Id (festival) prayers. If someone were to act or it occurred to him to adopt the known adhan as a means to announce the entry of the time for the 'Id prayer, that would not be accepted from him. Because the requirement for legislating or ... such an adhan was present in the time of the Prophet - may Allah's prayers and peace be upon him and his family - and yet that was not established as a recommended practice. So whoever establishes ... after the Prophet - may Allah's prayers and peace be upon him and his family - an adhan for the purpose of announcement is an innovator and one who commits religious innovation. This means that he is adding to the Prophet - may Allah's prayers and peace be upon him and his family - and ... in his state and the state of affairs, as it is said, is more eloquent than the spoken word. Therefore, it was reported from the Imam of the City of Migration, Malik ibn Anas - may Allah be pleased with him - that he said: "Whoever innovates in Islam a religious innovation that he sees as good, has claimed that Muhammad - may Allah's prayers and peace be upon him and his family - betrayed the message. Read the saying of Allah - Blessed and Exalted is He - : " He said - may Allah have mercy on him - : "And the end of this Ummah (Muslim community) will not be rectified except by what rectified its beginning. So whatever was not a religion at that time will not be a religion today."
Thus, drawing near to Allah - Mighty and Majestic - by legislating a form of worship that was not in the time of the Prophet - may Allah's prayers and peace be upon him and his family - while the requirement for it to be a Shari'ah (Islamic sacred law) in his time was present, is the very essence of religious innovation in the religion, and it has no relation to "unrestricted public benefit." This is if the requirement for adopting that public benefit was present in the time of the Prophet - may Allah's prayers and peace be upon him and his family - .
Then the Shaykh al-Islam Ibn Taymiyyah - may Allah have mercy on him - continues and says: And if the requirement was not present in the time of the Prophet - may Allah's prayers and peace be upon him and his family - one looks to see if the cause of this requirement for adopting that means is the neglect by Muslims of some of the rulings of the Shari'ah (Islamic sacred law). Then this neglect is what caused the introduction of another means that was not in the time of the Prophet - may Allah's prayers and peace be upon him and his family - resulting from not adopting what was in the Sunnah (the Prophet's way) this public benefit. In that case, it is not permissible to adopt it, because the cause of its requirement is the shortcoming of Muslims in carrying out some of the rulings of their religion.
An example of this is what is happening in many Islamic countries regarding the taxes that have burdened the shoulders of most Muslim peoples. Imposing these taxes as a public benefit to fill the state treasury; this is undoubtedly a public benefit. But what created these taxes? The failure to carry out the lawful means legislated by the Prophet - may Allah's prayers and peace be upon him and his family - which are the collection of various funds mentioned in some books of scholars of hadith, such as the book "Al-Amwal" (The Wealth) by Abu Ubayd, and the book "Al-Amwal" (The Wealth) by Ibn Zanjawayh, and other scholars who elaborated in detail on the wealth that must be collected, and that it should be prepared for the state treasury to carry out the interests of Muslims, whether they are general, high, or incidental. If Muslims adopt this Shari'ah (Islamic sacred law) legislated by the Messenger - may the prayers and peace of Allah be upon him - it will suffice them from imposing means to collect wealth and fill the state treasury with it. So in this case, it is not permissible to impose systems or impose means on Muslims. If the requirement for imposing them is present, but the cause for that is only their neglect of the system of imposing zakah (the obligatory alms), for example.
As for - and this is the end of the research on unrestricted public benefit - as for if the requirement for imposing a new system and a new means that was not customary in the time of the Prophet ... this requirement was not caused by the neglect of Muslims in what we mentioned of some of the rulings of the religion; then here, as long as this public benefit achieves a lawful objective that does not contradict the Shari'ah (Islamic sacred law) in any way, in this case it is permissible to adopt this means, and it falls under the category of unrestricted public benefit.
An example: with the same previous example; if we assume that the state carried out its duty of collecting wealth from the lawful ways, such as zakah (the obligatory alms) - for example - ... and the like, then an emergency occurred or an enemy attacked the lands of Muslims, and ... those in charge of the House of Wealth of Muslims found that these funds that were being collected through lawful ways were not sufficient to repel the attack of this enemy. In this case, it is permissible for the Muslim ruler to impose new taxes to repel that enemy from the lands of Muslims. Once the enemy is repelled, these taxes are lifted; because they were incidental to repelling that enemy ... .
Once we know this detail related to unrestricted public benefit, we then know the distinction between the misguided religious innovation and the public benefit that is permissible to adopt, and it is with this extreme precision ... .