Skeptics’ questions challenge faith on the internet, in the media and in universities. Some of these questions arise even from scholars, though often speaking outside their disciplinary expertise. And while most New Testament scholars agree on a number of key elements of Jesus’ ministry, other details are more debated, depending on the particular scholar’s assumptions.

As criticizing other people’s religion has become more acceptable in our culture, hostile critics of Christianity are stepping up their attacks against Jesus, with some radical popular skeptics denying even His existence.

Of course, denying His existence, or even the main elements of His ministry, is historically implausible. We have more accounts about Jesus, from within living memory of His ministry, than for almost any other ancient teacher.

Today most New Testament scholars agree on a number of key elements of Jesus’ ministry. For example, Jesus grew up in Nazareth, preached the Kingdom, taught in parables, was known by others for healing and exorcism, and was crucified under Pilate.

Nevertheless, skeptics’ questions challenge faith on the internet, in the media and in universities. Some of these questions arise even from scholars, though often speaking outside their disciplinary expertise. And while most New Testament scholars agree on a number of key elements of Jesus’ ministry, other details are more debated, depending on the particular scholar’s assumptions.

In this article, therefore, I will survey four reasons to believe that the Gospels are historically reliable, and address four common objections raised against their reliability. Most of these observations reflect research in my recent book, Christobiography: Memories, History, and the Reliability of the Gospels (Eerdmans, 2019).

Reasons to Believe

We have good reason to expect the Gospels to be historically reliable accounts. Calling them “reliable” does not suggest that the Gospels prove identical in all details or share identical perspectives, still less that after 20 centuries we can unearth evidence to support their every point. It does mean, where we can test them, the Gospels report real events and real teachings of Jesus, and that in them we genuinely meet Jesus.

The most accurate period of ancient biography was the period of the early Roman empire, precisely the period in which the Gospels were written. Further, the most reliable biographies were those about figures from within living memory of the biographer.

The Gospels’ overlap shows their dependence on and respect for sources. And finally, the Gospels retain elements that fit Jesus’ time and location better than those of the Gospels’ audiences.

1. Across the theological spectrum, most scholars today recognize the Gospels are ancient biographies.

Among ancient types of prose literature, normally only biographies focused on single historical figures. The one exception was a fairly rare form of ancient novel, but the Gospels cannot fit that designation. Most ancient novels were romances — a feature lacking in the Gospels.

The rarer form of novels that dealt with historical figures never dealt with recent figures as the Gospels do; such novels usually referred to characters who lived centuries earlier. Moreover, these novelists were not interested in reporting genuine information. They generally made up most of their stories.

By contrast, the overlap among the Gospels shows that they depend on prior information. This is what we expect from ancient biographies. Biography had evolved from praise-or-criticism speeches centuries earlier into much more clearly historically based works by the first century.

Then as today, biographers wrote from particular perspectives and chose which information to emphasize and which information to omit. Nevertheless, they were not supposed to make up events like novelists did. They depended on prior sources, written or oral, that they believed conveyed accurate information.

By modern standards, the most historically based period of ancient biography starts in the first century B.C. (with Cornelius Nepos) and runs through at least the second century A.D. (with Plutarch, Suetonius and Lucian). Before and after that period, we encounter much more homiletical license. The Gospels, however, fortuitously come from the most historically based period of ancient biography.

2. The Gospels are from within living memory.

Our best surviving biography of Alexander the Great comes from nearly five centuries after his death; Mark’s Gospel is usually dated to 34 to 45 years after Jesus’ death. Ancient historians and biographers freely admitted that when they recounted events from centuries earlier, they often had to depend on legends. The case was different, however, with figures from within the past generation or two, when they often could even interview witnesses.

Some people today question whether anyone would remember events in Jesus’ life by the time the Gospels were written. But while no one would claim that Jesus’ disciples remembered everything He said and did, they should have remembered more than enough to fill the Gospels.

Oral historians use the phrase “living memory” to refer to the period when people who knew the original witnesses might still be alive. After this period, legends are more likely to arise, although these legends often still contain information in condensed and packaged form.

Any Gospel written within the first century would be within living memory of Jesus’ ministry. A majority of scholars date all four canonical Gospels to the first century. All other so-called “gospels” are later than living memory — most of them centuries later.

Usually scholars date the Gospel of Mark to A.D. 64–75 (I prefer the earlier date), so roughly four decades after Jesus’ public ministry. If someone today suggested we cannot trust any witnesses’ claims about events that happened 40 years ago, we would not take them seriously. Most of us know someone (or are someone) who was around more than four decades ago.

Granted, we forget most experiences and certainly most details, but we do remember most particularly striking episodes. Presumably, many of Jesus’ miracles would qualify! Studies suggest that many events significant enough for us to remember after five years may stay with us even decades later, so long as our brains remain healthy.

Moreover, those who taught about Jesus were not simply modern Western consumers who can recheck our information on Google. They lived in a world that treasured memory. All our sources from the ancient Mediterranean world emphasize the importance of memory in education, from the elementary level up to the advanced level. Even today, in some parts of the world some Muslims who do not even understand Arabic can recite large parts of the Qur’an in Arabic from memory.

Disciples were learners at the advanced level. They were often in their late teens, one of memory’s most fertile periods. Teachers expected disciples to learn and pass on their teachings and example. This was true whether disciples were literate or illiterate, whether the instruction was in writing or oral. Unless Jesus’ disciples were highly unusual, we should expect them to have learned Jesus’ message and example thoroughly.

Not only would the disciples be expected to learn Jesus’ teachings, but they would regularly repeat them. As leaders in Jesus’ movement, they would recount these matters. Luke reports information passed down from “eyewitnesses and servants of the word” (Luke 1:2).

We can also be certain these stories circulated very widely in the first generation, making later alterations difficult. Luke writes that he is merely confirming the story of Jesus that Theophilus already knows (Luke 1:4). That does not leave Luke room to fabricate his story about Jesus.

3. The overlap shows their dependence on and respect for sources.

By the time Luke writes, many others have written accounts about Jesus (Luke 1:1). We do not have all of Luke’s sources today, but one of them seems to be Mark (whose grammar Luke improves). Because Luke and Matthew overlap on many other points, but do not seem to have known each other’s accounts of Jesus’ birth or Judas’ death, most scholars also believe they share another source or sources in common.

One way we can test ancient biographies’ fidelity to their sources is to compare them with those sources where those sources have survived. Where Matthew, Mark and Luke overlap, we find them even closer to one another than was typical among ancient biographies. This means that Matthew and Luke were writing information-based works.

Since Matthew and Luke wanted to report information, this also means they believed that Mark and their other shared material were information-based. And since they wrote fairly soon after their sources, they were in a much better position to evaluate the quality of these sources than are we modern scholars, who are limited to guesswork.

Indeed, within living memory of Mark’s composition, a Christian writer named Papias claimed to have it on good authority that Mark wrote down stories he heard firsthand from Peter. Mark’s dependence on Peter would help explain why Matthew and Luke treated Mark’s Gospel as such an important source! John’s Gospel may depend less on Mark because John shared a stature similar to Peter’s (John 13:23-25, 20:2-8).

Ideally, historians today would love to interview the earliest available witnesses. Of course, we ordinarily cannot interview witnesses for events 2,000 years ago. Luke, however, was in a position to interview contemporaries. He recounts his thorough acquaintance with the matters he reports (Luke 1:3).

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