There are four Gospels involved in the Bible - the Gospels according to Matthew, Mark, Luke and John. In these Gospels, we come across many sayings claimed to be by Jesus. They were composed between forty and eighty years after the departure of Jesus relying on some earlier documents which are now lost. Biblical scholars have identified some of these earlier documents as (1) 'Q' (German Quelle = 'Source'), a lost document in Aramaic, which reached the writers of the Gospels in a Greek translation, (2) ('Urmarcus' = Primitive Mark) an earlier draft of Mark's Gospel written on the basis of Peter's discourses about Jesus, and (3) 'L', a collection of reports about Jesus used only by Luke. A comparison of the Gospels will show that their authors used these lost documents in a somewhat free manner; they did not even hesitate to change some sayings contained in them to suit their own purpose.
The first Gospel to be written was that of Mark. It was written at Rome at least forty years after the so-called crucifixion of Jesus. The Gospel as we have it today is an expanded version of Urrnarcus, about which Papias, an early Christian writer, has the following to say:
"The elder John used to say, Mark having become Peter's interpreter, wrote down accurately whatsoever he remembered. It was not, however, in exact order that he related the sayings or deeds of Christ. For he neither heard the Lord not accompanied him, but subsequently as I said, attached himself to Peter who used to frame his teaching to meet the wants of his hearers, and not as making a connected narrative of the Lord's discourses."
It is not possible to say whether Urmarcus was expanded and revised to give us the Gospel of Mark as we have it by Mark himself or by some other person. Dr C. J. Cadoux who was Mackennal Professor of Church History at Oxford, thus sums up the conclusions of eminent Biblical scholars regarding the nature and composition of this Gospel:
"it was written after Peter's martyrdom (65 A. C.), and at a time when Mark, who had not himself been a disciple of Jesus apparently had none of the personal disciples of Jesus within reach by whose knowledge he could check his narrative. These circumstances of its composition account for the existence in it, side by side, of numerous signs of accuracy and a certain number of signs of ignorance and inaccuracy."
The Gospel of Matthew was written in Greek at Antioch about 90 C. E. The author made use of at least two lost documents; 'Q' and 'Urmarcus'. No independent scholar regards this Gospel as the work of Matthew the apostle of Jesus. Lf Matthew composed anything it must have been only 'Q'.
Regarding the liberties taken by the unknown author of this Gospel with the original material, C.J. Cadoux writes:
"But a close examination of the treatment he gives to his borrowings from Mark shows that he allowed himself great freedom in editing and embroidering his material in the interest of what he regarded as the rightful honouring of the great Master. The same tendencies are often visible elsewhere when he is producing 'Q' or providing matter peculiar to himself. Anything, therefore, strictly peculiar to 'Matthew' can be accepted as historical only with great caution."
The third Gospel, the Gospel of Luke, was written somewhere in Greece about the year 80 A.C. for the benefit of "the most excellent" Theophilus, probably a high official in the Roman Empire. It was an apologetic addressed to non-Jews. The writer, who was the friend and travel-companion of St. Paul, made use of at least three lost documents, two of these were indentical with those used by the writer of Matthews Gospel and the third was peculiar to himself. Luke, who wished to bring his Gospel in line with the Pauline point of view, took even greater liberties with his source than the writer of Matthews Gospel had done.
The Gospels of Mark, Matthew and Luke are called "the Synoptic Gospels", because they proceed on the basis of the same lost documents and have much in common. But the Gospel
of John is very different. The divinity and pre-existence of Jesus are affirmed in this Gospel alone, though never as a claim put forward by Jesus himself. In the opening lines of this Gospel,
the writer claims that the Divine Logos, the Word or Reason of God, Who created the world, had become incarnate in Jesus. The Gospel of John was written at or near Ephesus betwee11 the years 110 and ll5 of the Christian era by some unknown writer who was anti-semitically inclined: This is evident in his representation of Jews as the enemies of Jesus Christ (pbuh). No independent scholar regards it as the work of John the Son of Zebedee, who, according to R. H. Charles, Alfred Loisy, Robert Eisler, and other scholars, was beheaded by Agrippa I in the year 44 A.C., long before the Fourth Gospel was written. The modern Biblical scholars doubt the genuineness not only of the writer's own views expressed in this Gospel, but also of the words put by him in the mouth of Jesus Christ. C. J. Cadoux writes:
"The speeches in the Fourth Gospel (even apart from the early messainic claim) are so different from those in the Synoptics, and so like the comments of the Fourth Evangelist himself, that both cannot be equally reliable as records of what Jesus said: Literary veracity in ancient times did not forbid, as it does now, the assignment of fictitious speeches to historical characters: the best ancient historians made a practice of composing and assigning such speeches in this way."
 Roberts and Donaldson (editors), The Anre·Nicene Father, Vol.I, pp. 154, 155.
 C.J. Cadoux: The Lyk ryffcsus, Penguin Books, p.l3.
 C.J. Cadoux; The Life of Jesus, Penguin Books, pp. 14,15.
 C.J. Cadoux : The Life of Jesus, p. 16.