Biblical scholars love to debate dates and to provide a number of potential scenarios as to the historical truth behind when books of the Bible were written.
Much of what biblical scholars do is to take the evidence they have and provide their best guess as to what happened.
The majority of modern biblical scholars believe that the Gospel of Mark was the first written Gospel, dated to between 50-70 AD.
The Early Church Fathers thought that the Gospel of Matthew was the first gospel to be written. In fact, the sequence of gospels in the New Testament reflects this traditional order of composition: Matthew, Mark, Luke and John.
All scholars generally agree that the Gospel of John was the last to be written, but there is some debate as to who was the first.
What the Early Church Fathers said
In the 4th century St. Augustine wrote, in The Harmony of the Gospels:
Now, those four evangelists whose names have gained the most remarkable circulation over the whole world, and whose number has been fixed as four — it may be for the simple reason that there are four divisions of that world through the universal length of which they, by their number as by a kind of mystical sign, indicated the advancing extension of the Church of Christ — are believed to have written in the order which follows: first Matthew, then Mark, thirdly Luke, lastly John.
Hence, too, [it would appear that] these had one order determined among them with regard to the matters of their personal knowledge and their preaching [of the gospel], but a different order in reference to the task of giving the written narrative.
Origen in the 3rd century shared a similar belief in his Commentary on Matthew 1:
Concerning the four Gospels which alone are uncontroverted in the Church of God under heaven, I have learned by tradition that the Gospel according to Matthew, who was at one time a publican and afterwards an Apostle of Jesus Christ, was written first and that he composed it in the Hebrew tongue and published it for the converts from Judaism.
The second written was that according to Mark, who wrote it according to the instruction of Peter, who, in his General Epistle, acknowledged him as a son, saying, 'The church that is in Babylon, elect together with you, salutes you and so does Mark my son.' And third, was that according to Luke, the Gospel commended by Paul, which he composed for the converts from the Gentiles. Last of all, that according to John.
While both arguments certainly have great weight, in reality we can't know for certain who wrote their Gospel first.
What makes it even more difficult is the fact that the stories of Jesus' life were initially communicated orally, before they were ever written down.
How it affects us
Spiritually speaking, the question always remains: Does it even matter? Sometimes we have to sit with the reality that we were not present 2,000 years ago and can't with 100% certainty know what happened.
God knows and that should be sufficient for us.
What matters the most is the content of each Gospel and how the Holy Spirit was behind it all. We can rest easy knowing that what we read was inspired by God.
