To call people to Allah is the duty of every responsible and conscientious Muslim. Since there is no priesthood in Islam or sacerdotal class among Muslims, the duty of the call to Allah cannot be limited to an ill-conceived and imaginary group called the 'men of religion as is the case with other religions.' In Islam, everyone is a man (or woman) of religion and everyone will be accountable to Allah as to whether or not one fulfilled their obligations sincerely and to the best of their abilities.
Urging Muslims to own up to their responsibilities in this respect, Almighty Allah Says (what means): “And who is better in speech than one who calls to Allah and does righteousness and says, ‘Indeed, I am of the Muslims.’” [Quran 41: 33]
Therefore, one need not be a profound scholar or a great jurist to call others to Islam. A Muslim should better be a caller to Islam by his good conduct than by eloquent oration, for to preach others to do something not practically embodied in the preacher's character is a vain attempt to win hearts and minds. Moreover, doing so incurs Allah’s displeasure, as He, the Almighty Says (what means): “O you who believe! Why do you say that which you do not do? Most hateful it is with Allah that you say that which you do not do.” [Quran 61:2-3]
The well-known adage “Actions speak louder than words” was well embodied in the Islamic history, namely the spread of Islam in many non-Muslim countries- like parts of Asia, Africa and Europe- through the good conduct of Muslim merchants who came into commercial contacts with the people of those countries.
Hereunder is a brief survey of that peaceful spread of Islam:
Southeast Asia
By the 14th century CE, as Islam made its way through Indian and Chinese merchants into the area of today’s Malaysia, Buddhist and Hindu influences gave way. Islam became the source of legitimacy for the Malay feudal rulers. It was during this period that Islamic and Malay identities combined together, though many Hindu and pre-Hindu customs and practices remained part of the Malay cultural and social mix.
Muslim influence in Southeast Asia is at least six centuries old, i.e., it was present by 1400 A.D. Some argue that the Islamic presence there goes back to at least 1100 A.D. in the earliest areas of Islamic influence, such as in Aceh and northern Sumatra in Indonesia. Whatever exact dates and sources one chooses to support, there is no doubt that the acceptance of Islam by many nations in present-day Malaysia, southern Thailand, Indonesia, Brunei, and the southern Philippines occurred within a few hundred years.
In the year 1500, the historian Anthony Reid notes that Islamic influence was present in coastal ports of Sumatra, Java, and Malaysia. Southeast Asian peoples came into direct contact with Muslim traders who had been not just to India, but also to Arabia. Arabic scholars also came to Malaysia and Indonesia, facilitating information about the new religion.
The successful spread of Islam in Indonesia, Malaysia, and the Philippines owed much to the introduction of the Noble Quran and other Islamic books and references.
Today, 90% of Indonesians are Muslims, while over half of Malaysia's population is Muslim. In the Philippines, where the Spanish (and later Americans) won the war for religious converts, only 5% of the population is Muslim.
Africa
The growth of cities was both a cause and effect of the spread of Islam and economic growth in Muslim-ruled areas in Africa. Cultural developments in literature, arts and sciences, manufacturing and trade accompanied the spread of Islam and its influence on religious, intellectual, economic and political life in those regions.
Although unified Muslim rule lasted only about a century, Islam kept spreading and Muslim culture and society flourished.
Before 1500, Islam spread widely in sub-Saharan Africa. The first town south of the Sahara that became majority Muslim was Gao on the Niger River in Mali before 990, when a ruler accepted Islam. Over the centuries, many rulers followed. By 1040, groups in Senegal became Muslims. From them Islam spread to the region of today’s Senegal, west Mali, and Guinea. After the Soninke of the Kingdom of Ghana became Muslims about 1076, Islam spread along the Niger River.
Muslims established the kingdom of Mali in the thirteenth to fifteenth centuries, and Songhai from1465 to 1600. Farther east, Kanem-Bornu near Lake Chad became Muslim after 1100.
In West Africa, as was the case with Southeast Asia, it was traders who introduced Islam, and many rulers accepted it first, followed by others. African Muslim scholars became established in the major towns like Timbuktu, and they taught, wrote and practiced Islamic law as judges. Islam was established in West Africa throughout the Sahel belt and along the Niger River into today’s Nigeria.
It was famous trade routes which led to the empire of Ghana and connected prominent African places like Timbuktu (in Mali), the present Nigeria, Tripoli and Tunisia. These routes had made all the above mentioned places famous trade centers. These centers of trade invariably became centers of Islamic learning and civilization. New ideas came through visiting traders in the field of administrative practices.
In East Africa, traders had spread Islam down the coast by the tenth century, and it gradually developed further in the following centuries. In the Sudan, south of Egypt, the population of Nubia gradually became Muslim during the fourteenth century, through immigration of Muslim Arab tribesmen. Muslim rule and influence, however, did not extend south of Khartoum, where the Blue and White Niles before 1500.
Look at the beginnings of this religion and how it unified the Arabian Peninsula, while Arab loyalties were divided with unrestrained enmity and maliciousness everywhere. Look at how, as Muslims, they united, cast aside their differences, and became a firm brotherhood of faith!
Take a quick look at the early extraordinary conquests of Islam. Then at how the Muslims defended and maintained their position, even while their enemies fiercely opposed them!
After establishing their state, they spread to the farthest parts of the world and continued their conquest of hearts and armies there. Many emperors and nations fell into their hands, including the then powerful nations of Persia and Rome. Muslims easily overcame them and their surrounding lands even though their enemies were strong in warfare and well-supplied with arms. But the Muslims were victorious because of the virtues and merits of their religion, the strength of their faith, and Allah’s aid in assisting them until the boundaries of Islam spread from the East of the earth to its West.
This resulted as one of the great signs of Allah, proofs of His religion, and a miracle of His Prophet 
. Thus, people entered into Allah’s religion in multitudes with peace of mind and tranquillity, not by force or compulsion.
Whoever examines this fact closely will see that this religion is the truth, which will always reject anything false, even when it becomes tremendously appealing and reaches its zenith on the world stage. This is an undeniable fact which is easily seen by simple reasoning.
Among the most persistent falsehoods about Islam in the West today is the lie about forcible conversions to Islam. Many Westerners continue to believe that Islam is so widespread in the world today simply because of a 'holy campaign of terror' carried out by the early Muslims to convert non-Muslims to Islam. According to these fabrications, non-Muslims were given the choice of Islam or death.
How can we confront such misconceptions? First, there is no need to be apologetic. We Muslims should search for the truth and present it as it is.
This is how we have been instructed by Allah Almighty, in words (which means): "…Say: "The truth is from your Lord, so whoever wills – let him believe; and whoever wills – let him disbelieve.'" [Quran 18:29]
Islam is the religion of truth. The Quran is the book of truth; Allah Says (what means): "And with the truth We have sent it [i.e., the Quran]..." [Quran 17:105] And also: "So rely upon Allah; indeed, you are upon the clear truth." [Quran 27:79]
Therefore, we should ask ourselves first, before we are asked by anyone else, what is the truth? Did Muslims really force others to convert to Islam? Is there any evidence for consistent forcible conversion throughout Islamic history? As a matter of fact, there is no such evidence anywhere in the history of Islam.
Many distinguished Western historians have attested to this fact in their books, foremost amongst them are Sir Thomas W. Arnold in 'The Preaching of Islam', Marshall G. Hodgson in 'The Venture of Islam', Albert Hourani in 'A History of the Arab People', Ira Lapidus in 'A History of Islamic Societies', L.S. Starorianos in 'A Global Hisotry, the Human Heritage', and many others. In fact, there is a plethora of evidence to the contrary.
Some contemporary writers whose works are influenced by the enemies of Islam claim that these unprecedented victories were driven purely by materialism, which is completely baseless. They claim that the successful spread of Islam was possible because of the deterioration and downfall of the lands of the Caesar of Rome, and the material prosperity in Arabia. This point alone is sufficient enough to invalidate their claim.
Was there any power existing in the Arabian Peninsula before Islam capable of confronting even the weakest government? In their zeal, Muslims conquered the strongest governments and most powerful nations of the world. The enemies resisted with massive arms and vast armies, and every means in their power, but tyrannical rule was replaced by the Laws of the Quran and the Religion of Justice.
How can they misrepresent the conquests of Islam and its growth with the claim that material gain was the prime factor behind it? By such fabricated stories, they meant to tarnish Islam, promoting the accusations of the enemies of Islam, without understanding the truth.
The continuous existence of this religion, even under dangerous circumstances, is one of its distinguishing signs; despite the fact that its enemies collaborate for its total extermination; Allah Says (what means): "They [i.e., the disbelievers] want to extinguish the light of Allah with their mouths, but Allah will perfect His light, although the disbelievers dislike it." [Quran 61:8]
This is the true religion of Allah. If the necessary strength was assembled to repel the oppressors and end their systems of injustice, then no religion other than Islam would remain on the earth, and all of its inhabitants would accept it without compulsion or coercion, because it is the religion of truth, the natural religion, the religion of unity and social welfare. But its people are negligent, weak and disunited, and they are impeded by the influence of their enemies, preventing them from advancing. There is no might or ability except from Allah.
