One of the challenges many readers face when approaching the Bible is understanding the differences between the four Gospels. While Matthew, Mark, Luke, and John all tell the story of Jesus, they sometimes present timelines and details that appear to be in conflict. For skeptics, these differences are often used as ammunition against the reliability of Scripture. For believers, they can raise difficult questions. In his book, The Science Behind the Story of Jesus, John Zachary addresses these issues with both scholarly precision and scientific clarity—showing that what once looked like contradictions are, in fact, complementary truths.
A central theme in Zachary’s analysis is the role of different Jewish calendars. During the first century, Jewish groups such as the Pharisees and Sadducees followed separate calendrical systems. This meant that events like the Passover could be observed on different days depending on which system was being used. For centuries, this has caused confusion in reconciling the Gospel accounts of the crucifixion. But Zachary demonstrates that when you overlay these calendars with historical and astronomical data, the supposed contradictions disappear. What emerges is a unified timeline that confirms the accuracy of the Gospels.
For example, in John’s Gospel, Jesus’s crucifixion appears to take place on a different day than in the synoptic accounts. Many have seen this as irreconcilable, but Zachary shows how the use of different calendars explains the variation. By calculating lunar cycles and aligning them with Jewish practices of the time, he proves that both perspectives are accurate, each reflecting the tradition of a specific Jewish sect. Far from undermining the reliability of Scripture, this strengthens it by showing how diverse cultural practices fit together in harmony with the biblical record.
What makes this section of the book so powerful is not just the technical explanation but its spiritual impact. For centuries, critics have pointed to these differences as evidence against Christianity. Zachary’s research flips that argument on its head. By grounding the Gospel accounts in real history and science, he demonstrates that Scripture’s truth withstands the closest scrutiny. This doesn’t just answer academic questions—it restores confidence for believers who may have wrestled with doubt.
As with other sections of the book, Zachary balances scholarly depth with accessibility. Executive summaries provide a clear overview, while appendices dive deep into the data for readers who want to follow the calculations step by step. The fictional thread, “Tourists from the Future,” adds a unique touch, allowing readers to imagine themselves in Jerusalem, watching these events unfold in real time while understanding the cultural dynamics at play.
Final Reflection: John Zachary’s work on the Gospels is a vital contribution to both faith and scholarship. He shows that differences in the biblical accounts are not contradictions, but reflections of a complex historical reality that, when examined closely, only strengthens the case for the truth of Jesus’s life, death, and resurrection. For anyone who has ever struggled with these questions, The Science Behind the Story of Jesus offers clarity, assurance, and a renewed confidence in the reliability
