God’s salvation and written revelation are inseparable. When the Lord intervenes to save His people, He also inspires Scriptures to guide them. As God redeemed ancient Israel from slavery, He moved Moses to author Genesis–Deuteronomy. During the periods of conquest, monarchy, and exile, our Creator inspired prophets to write the Historical, Poetic, and Prophetic Books of the Old Testament. So, when the Lord acted definitively and finally in Christ to save sinners, the New Testament was inevitable.
In canonical order, the gospel of Mark is the New Testament’s second book. Yet when it comes to the four Gospels, it may have been the first one written. For various reasons, most biblical scholars today believe Mark was written first, followed by Matthew and Luke, who followed Mark’s outline. Some scholars think that John also consulted Mark’s gospel. Whatever the case, the writing process for these other gospels involved something more than simply adding information to Mark.
It should not trouble us if Mark was written first and others relied heavily on his work though. If Mark’s gospel is divinely inspired, why would you not use it? The gospel of Mark is almost certainly a record of Peter’s essential preaching about Jesus, as the early church fathers unanimously assert. The style of the book confirms this. We can imagine the tight stories with brief narrative connections we find in Mark’s gospel as being texts originating from individual sermons.
Despite being Mark’s main source, Peter did not write this book. Early church tradition identifies the author as John Mark, the son of a Christian woman in Jerusalem who had personal contact with Peter (Acts 12:6–25). This same John Mark was the subject of a disagreement between Paul and Barnabas that caused them to go their separate ways for a time (Acts 15:36–41). By the end of Paul’s life, however, the Apostle and John Mark reconciled (2 Tim. 4:11). Some extrabiblical traditions say that Mark established the church in Egypt and started a catechetical school there to teach people the Christian faith.
All indications are that Mark wrote his gospel to proclaim to as many people as possible that Jesus is the Son of God, as his gospel begins and essentially ends with that truth (Mark 1:1; 15:39). His simple, vivid writing style and explanations of Jewish customs prove that he wanted a wide audience, including non-Jews, to be able to read his book.