The Quran says, “O Prophet invite to the Way of your Lord with wisdom and excellent preachings and argue with the people in the best manner”(16:125). In this way the Quran not only emphasized the use of the best possible substance but also the application of best possible method.
While taking its message across, The Quran further says “and do not dispute with the people of the Book except in the best manner, save with those who do wrong, and say to them, we have believed in that which has been sent down to us as well as in that which has been sent down to you. Our God and your God is one and to Him we have surrendered (as Muslims)” (29:46).
The Quran also tells us what kind of substance and what kind of method we should use while preaching and arguing with the people. The common points of faith are belief in the existence and Unity of Allah, belief in their scriptures and belief in their Prophets as the Messengers of Allah. The method to be applied according to the verse should be by taking a start from the common points of faith.
On the other hand if a start is taken directly from the points in dispute, it will have negative effect. That’s why the Quran lays emphasis on the use of best possible substance as well as the application of best possible method. All the letters sent by the Prophet (peace be upon him) to the Christian heads of states and tribes started with stressing the common points of faith.
In this connection the Quran cites an excellent example as to how one point of common faith can arouse sympathies towards each other. When the Romans who were Christians but believed in the Unity of Allah were defeated by the Persians, the Muslims of Makkah got very disappointed.
The people of Quraish tribe started joking with them saying that in the same manner as the Persians defeated the believers in the Unity of Allah, they (the Quraish) too will defeat the Muslims whenever they fought with them.
During this period, a few verses of Surah Ar-Room of the Quran were revealed which predicted that very soon the Romans will emerge as the victors and on that day the Muslims will rejoice (30:3,4). And the Romans did emerge as victors within a short span as predicted by the Quran.
The best way to preach is by reasoning as explained by the Quran with reference to the way Hazrat Ibrahim tried to convince the people about the authenticity of his message.
Hazrat Ibrahim had to deal with people professing different kinds of faith. Some of them took stars as their gods, some took moon and some took the sun as their gods and worshipped them.
To those who worshipped stars, he said that the star was his god when he saw the star in the night. But when in the morning he found that no star was visible anywhere he said how could he accept an object as his God which was apt to set.
Then to those who worshipped moon he said that the moon was his god when he saw it in the night. But when the moon disappeared in the morning, he exclaimed that surely one was likely to go astray without guidance from Allah. And finally to those who worshipped the sun, he said that the sun was his god which was the most powerful of all when he saw the sun in the morning. But when the sun disappeared in the evening, he said to the people that he was free of their guilt of associating partners with Allah.
Thus, in each case, Hazrat Ibrahim accepted the version of the concerned people first but rejected it subsequently when he came to know about its fallacy on the basis of solid proof. That’s why about the method so applied the Quran says “that was the reasoning about Us that We gave to Ibrahim (to use) against his people”(6:83).
In addition to the above, the Quran tells us about many facts and realities that can be used as substance in order to make such arguments more meaningful. The first instance that can be quoted in this connection could be the existence of harmony in the creation, a fact that cannot be denied on any score whatsoever, about which the Quran says “He raised the heavens high and set the balance”(55:7).
According to the verse, after the creation of all the stars, planets and other celestial bodies, Allah placed them in proper order so as to maintain the requisite degree of equilibrium and balance.
As the Quran says “the sun must not catch up the moon, nor does the night outstrip the day. Each one is travelling in an orbit with its own motion”(36:40).
It says again “Have they never looked up to the sky above them (and observed) how We made it and adorned it and there is no flaw in it”(50:6). It further says “such is the artistry of Allah Who arranges all things in perfect order”(27:88).
That’s why the renowned scientist Einstein said “God reveals himself in the harmony that exists in the creation”. According to Martin Lings "harmony is the imprint of Oneness upon multiplicity and the Quran draws attention to that harmony for man’s meditation.
Another fact worth quoting in this connection could be the creation of the universe itself about which the Quran says “do the non-believers not see that the heavens and the earth were joined together, then we separated them”(21:30). The Arabic word “fataq” occurring in this verse implies separation by force or as a result of split or explosion.
The modern science has now found that originally the entire universe was a gaseous mass consisting of hydrogen and a certain amount of helium gases that was slowly rotating to which also there is a clear reference in the Quran (41:11).
After condensation and contraction, it turned into a super dense agglomeration of matter and finally got split through what the scientists call big bang. The fragments so separated from one another took the shape of billions of galaxies comprising stars, planets and other celestial bodies. This fact is further confirmed by another Quranic verse which says “I seek refuge with the Lord of Dawn (falaq)” (133:1).
The Arabic word “falaq” implies that which comes into being as a result of split or explosion. That’s why in another Quranic verse (6:96), the word “faliq” from the same root, has been used for the daybreak from the darkness (Dawn) which obviously occurs through a split, when the sun-rays pierce through the darkness of the night.
In this way, many other facts and instances narrated in the Quran can be used as the basis of arguments in line with the Quranic verse (telling the Prophet) “Say thou I do invite unto Allah on evidence clear as the seeing with one’s eyes”(12:108).