«So, Luke, the co-laborer of Paul, wrote down in the form a book the Gospel which he preached» (Irenaeus of Lyons. Against Heresies, 3.1.1; compare Eusebius of Caesarea. Church History, 5.8).
«As one can gather from his writings, Luke, the doctor from Antioch, was very knowledgeable in the Greek language. The author of the Gospel and Paul’s follower, he accompanied the apostle in all his journeys. Here is what Paul said of him: «And we have sent with him the brother, whose praise is in the gospel throughout all the churches (Corinthians) [2 Cor 8:18]; «Luke, the beloved physician, and Demas greet you» (Colossians) [Col 4:14], «Only Luke is with me» (Timothy) [2 Tim 4:10]. The other excellent work written by Luke, «Acts of the Apostles», covers events during Paul’s second year in Rome, which was the fourth year of Nero’s reign [57/58 NE]. On this basis we conclude that this book was written in this city… Some believe that when Paul says in his epistle: «according to my gospel, [Rom 2:16], he refers to the book of Luke [the Greek for Gospel is «Good News)], and that Luke knew the stories of the Gospel not only from Paul who didn’t see the Lord in the flesh, but also from other apostles. He mentions it in the beginning of his work: «…Even as they delivered them unto us, which from the beginning were eyewitnesses, and ministers of the word.» [Lk 1:2]. So, he wrote the Gospel on the basis of what he had heard from others, while «Acts of the Apostles» was written out of his own experience» (Jerome of Stridon. On Famous Men, 7).
In the prologue to his Gospel (Lk 1:1—4), Luke states the purpose for writing the book – to pull together the reliable information about Jesus and to relate it in an orderly manner. Many biblical scholars consider Luke’s Gospel to be highly accurate in its chronology as well as historical and geographical detail. For example, the other evangelists refer to the Galilean body of water as the sea, whereas Luke is more precise in naming it a lake (see Lk 5:1) – its water is fresh. Luke goes as far as to name even the smallest settlements in Judea. For example, he is the only one who mentions the city of Nain (see Lk 7:11). As a physician, Luke periodically throws in medical terms (Lk 4:38; 5:12; 14:2 and other).
The Book of Acts, also written by Luke, is an important source that complements the four Gospels.
The Gospel of John
The Gospel of John was written by the end of the 1st century. Tradition holds that it was compiled by John the Theologian, the son of Zebedee (see Mt 10:2; Mk 3:17; Lk 6:14; Jn 21:2, 24).
«Then, John, the disciple of Jesus who lay on His bosom [Jn 13:23], also published his Gospel during his time in Ephesus in Asia» (Irenaeus of Lyons. Against Heresies, 3.1.1; compare Eusebius of Caesarea. Church History, 5.8).
«John, the apostle, the one especially loved by Jesus [Jn 21:20, 24], the son of Zebedee and the brother of Jacob who was beheaded by Herod after the sufferings of the Lord, last of all wrote his Gospel at the request of some bishops in Asia who contended against Cerinthus and other heretics, especially the teachings of Ebionites who taught that Christ didn’t exist before Mary. So, John was asked to speak in defense of the doctrine of Divine Birth. There was yet another reason: having read the works of Matthew, Mark, and Luke, John approved of their narratives and confirmed that they contained the truth, noting that these narratives only describe was happened during the one year after John [the Baptist] was put in prison and executed. So, he himself wrote about a period preceding John’s imprisonment, and it can be a revelation for those who diligently read the works of the Gospel-writers. In addition, this consideration removes the contradictions that seemed to exist between the text of John and others… On the fourteenth year after Nero [82 NE] Domitian began the second persecution against Christians. John was exiled to the island of Patmos and wrote there the Apocalypse, which was later commented on by Justin Martyr and Irenaeus. But after Domitian’s death [96 NE] and the abolition of his cruel decrees, John returned to the city of Ephesus and, remaining there until the arrival of the emperor Trajan, contributed in every way to the planting of churches throughout Asia. Died of old age in the 68th year after the Passion of the Lord and was buried near Ephesus» (Jerome of Stridon. On Famous Men, 7; compare Eusebius of Caesarea. Church History, 3.24.7—14).
The Gospel of John was written to emphasize the divinity of Jesus Christ and to supplement what was lacking in the Gospels of Matthew, Mark, and Luke. John calls himself a «disciple whom Jesus loved» (Jn 13:23; 19:26; 20:2; 21:7, 20). He belonged to the small circle of apostles whom Jesus had singled out to be with him more often. John also includes several episodes not found in the other Gospels.
The Apocryphal Gospels
In addition to the generally accepted four Gospels, there is a large corpus of gospel texts that were not included in the New Testament canon. These are usually called Apocrypha (from the Greek ἀπόκρῠφος, «hidden», «mysterious», «secret»). This name was originally given only to the heretical books that were kept in secret. Later, all the works of Jewish and Christian origin that were not part of the Bible came to be called apocryphal. More than fifty apocryphal gospels have survived to this day in varying degrees of preservation.
In the process of forming the Gospel canon, the first books to be rejected were those with heretical content that contradicted Holy Tradition. The same thing happened to the books that contained lacunae or had not been preserved in a complete form. Later, the Pseudepigrapha, attributed to some famous authors, were rejected too because of insufficient evidence for their authenticity.
The Gospel canon
Irenaeus of Lyon (c. 130 – 202) was one of the first supporters of the canonicity of the Gospels of Matthew, Mark, Luke, and John: «The number of the Gospels cannot be more or less than what it is. For since there are four cardinal directions, the four winds, and since the Church is scattered all over the earth, and since the Gospel and the Spirit of life are the pillar and ground of the Church, the Church should have four pillars, spreading the fragrance of incorruptibility everywhere and reviving all men» (Against Heresies, 3.11.8). He criticized those who rejected the Gospel of John (the Alogi) or accepted only the Gospel of Luke (the Marcionites), as well as those who accepted or composed apocryphal hagiographies of Jesus (Gnostics for the most part).
Around the same time, a list of New Testament books, later called the Muratorian Canon, was compiled. The most probable author of the list, Hippolytus of Rome (c. 170 – c. 235), recognized only four Gospels as canonical.
This view was also shared by Origen (c. 185 – 254), Eusebius of Caesarea (c. 263 – 340), Athanasius the Great (296 – 372/373), Cyril of Jerusalem (315 – 386), Gregory the Theologian (329 – 389), Amphilochius of Iconium (c. 340 – after 394) and other early Christian writers.
The Council of Laodicea (343/363) decreed: «Rule 59. Let no psalm composed by a private person or any non-canonical book be read in the Church but only the canonical books of the New and Old Testaments». Later, after 363, the 60th rule was added to the acts of the Council with a list of the canonical books: "…these are the books of the New Testament: the four Gospels, Matthew, Mark, Luke, and John…».
The first Council to adopt the present-day canon of New Testament books was the Council of Hippo that took place in North Africa in 393. However, the decrees of this Council have been lost. Their summary was read and adopted by the Council of Carthage in 397: «Rule 47. Apart from the canonical books, nothing else is to be read in the Church under the name of divine Scripture. The canonical books are as follows: …of the New Testament: the Gospels, four books…».
«Diatessaron» by Tatian
Tatian the Syrian was a disciple of Justin the Philosopher (circa 112/120 – circa 180/185), a Christian writer and apologist. By the end of his life he fell into heresy. He is most known for his book «Diatessaron»