A comparison of Christianity with Muhammedanism or with any other religion must be preceded by a statement of the objects with which such comparison is undertaken, for the possibilities which lie in this direction are numerous. 

The missionary, for instance, may consider that a knowledge of the similarities of these religions would increase the efficacy of his proselytising work: his purpose would thus be wholly practical. The ecclesiastically minded Christian, already convinced of the superiority of his own religion, will be chiefly anxious to secure scientific proof of the fact: the study of comparative religion from this point of view was once a popular branch of apologetics and is by no means out of favour at the present day. Again, the inquirer whose historical perspective is undisturbed by ecclesiastical considerations, will approach the subject with somewhat different interests.

 He will expect the comparison to provide him with a clear view of the influence which Christianity has exerted upon other religions or has itself received from them: or he may hope by comparing the general development of special religious systems to gain a clearer insight into the growth of Christianity. Hence the object of such comparisons is to trace the course of analogous developments and the interaction of influence and so to increase the knowledge of religion in general or of our own religion in particular.

A world-religion, such as Christianity, is a highly complex structure and the evolution of such a system of belief is best understood by examining a religion to which we have not been bound by a thousand ties from the earliest days of our lives.

 If we take an alien religion as our subject of investigation, we shall not shrink from the consequences of the historical method: whereas, when we criticise Christianity, we are often unable to see the falsity of the pre-suppositions which we necessarily bring to the task of inquiry: our minds follow the doctrines of Christianity, even as our bodies perform their functions—in complete unconsciousness. 

At the same time we possess a very considerable knowledge of the development of Christianity, and this we owe largely to the help of analogy. Especially instructive is the comparison between Christianity and Buddhism. No less interesting are the discoveries to be attained by an inquiry into the development of Muhammedanism: here we can see the growth of tradition proceeding in the full light of historical criticism. 

We see the plain man, Muhammed, expressly declaring in the Qoran that he cannot perform miracles, yet gradually becoming a miracle worker and indeed the greatest of his class: he professes to be nothing more than a mortal man: he becomes the chief mediator between man and God. The scanty memorials of the man become voluminous biographies of the saint and increase from generation to generation.

Yet more remarkable is the fact that his utterances, his logia, if we may use the term, some few of which are certainly genuine, increase from year to year and form a large collection which is critically sifted and expounded. The aspirations of mankind attribute to him such words of the New Testament and of Greek philosophers as were especially popular or seemed worthy of Muhammed; the teaching also of the new ecclesiastical schools was invariably expressed in the form of proverbial utterances attributed to Muhammed, and these are now without exception regarded as authentic by the modern Moslem.

 In this way opinions often contradictory are covered by Muhummed's authority. The traditions concerning Jesus offer an analogy. Our Gospels, for instance, relate the beautiful story of the plucking of the ears of corn on the Sabbath, with its famous moral application, "The Sabbath was made for man, and not man for the Sabbath." A Christian papyrus has been discovered which represents Jesus as explaining the sanctity of the Sabbath from the Judaeo-Christian point of view. "If ye keep not the Sabbath holy, ye shall not see the Father," is the statement in an uncanonical Gospel. In early Christian literature, contradictory sayings of Jesus are also to be found. 

Doubtless here, as in Muhammedan tradition, the problem originally was, what is to be my action in this or that question of practical life: answer is given in accordance with the religious attitude of the inquirer and Jesus and Muhammed are made to lend their authority to the teaching. Traditional literary form is then regarded as historical by later believers. Examples of this kind might be multiplied, but enough has been said to show that much and, to some extent, new light may be thrown upon the development of Christian tradition, by an examination of Muhammedanism which rose from similar soil but a few centuries later, while its traditional developments have been much more completely preserved.

 Such analogies as these can be found, however, in any of the world-religions, and we propose to devote our attention more particularly to the influences which Christianity and Islam exerted directly upon one another. While Muhammedanism has borrowed from its hereditary foe, it has also repaid part of the debt. By the very fact of its historical position Islam was at first indebted to Christianity; but in the department of Christian philosophy, it has also exerted its own influence. 

This influence cannot be compared with that of Greek or Jewish thought upon Christian speculation: Christian philosophy, as a metaphysical theory of existence, was however strongly influenced by Arabian thought before the outset of the Reformation. On the other hand the influence of Christianity upon Islam—and also upon Muhammed, though he owed more to Jewish thought—was so extensive that the coincidence of ideas upon the most important metaphysical questions is positively amazing. There is a widespread belief even at the present day that Islam was a complete novelty and that the religion and culture of the Muhammedan world were wholly alien to Western medievalism. 

Such views are entirely false; during the Middle Ages Muhammedanism and Western culture were inspired by the same spirit. The fact has been obscured by the contrast between the two religions whose differences have been constantly exaggerated and by dissimilarities of language and nationality. 
o retrace in full detail the close connection which unites Christianity and Islam would be the work of years. Within the scope of the present volume, all that can be done is to explain the points of contact between Christian and Muhammedan theories of life and religion. 

Such is the object of the following pages. We shall first treat of Muhammed personally, because his rise as a religious force will explain the possibility of later developments.
This statement also explains the sense in which we shall use the term Christianity. Muhammedanism has no connection with post-Reformation Christianity and meets it only in the mission field. Practical questions there arise which lie beyond the limits of our subject, as we have already indicated. Our interests are concerned with the mediaeval Church, when Christianity first imposed its ideas upon Muhammedanism at the time of its rise in the East, and afterwards received a material extension of its own horizon through the rapid progress of its protégé. Our task is to analyse and explain these special relations between the two systems of thought.
The religion now known as Islam is as near to the preaching of Muhammed or as remote from it, as modern Catholicism or Protestant Christianity is at variance or in harmony with the teaching of Jesus. The simple beliefs of the prophet and his contemporaries are separated by a long course of development from the complicated religious system in its unity and diversity which Islam now presents to us. 

The course of this development was greatly influenced by Christianity, but Christian ideas had been operative upon Muhammed's eager intellectual life at an even earlier date. We must attempt to realise the working of his mind, if we are to gain a comprehension of the original position of Islam with regard to Christianity. The task is not so difficult in Muhammed's case as in that of others who have founded religious systems: we have records of his philosophical views, important even though fragmentary, while vivid descriptions of his experiences have been transmitted to us in his own words, which have escaped the modifying influence of tradition at second hand. 

Muhammed had an indefinite idea of the word of God as known to him from other religions. He was unable to realise this idea effectively except as an immediate revelation; hence throughout the Qoran he represents God as speaking in the first person and himself appears as the interlocutor. Even direct commands to the congregation are introduced by the stereotyped "speak"; it was of primary importance that the Qoran should be regarded as God's word and not as man's.

 This fact largely contributed to secure an uncontaminated transmission of the text, which seems also to have been left by Muhammed himself in definite form. Its intentional obscurity of expression does not facilitate the task of the inquirer, but it provides, none the less, considerable information concerning the religious progress of its author. Here we are upon firmer ground than when we attempt to describe Muhammed's outward life, the first half of which is wrapped in obscurity no less profound than that which veils the youth of the Founder of Christianity.