The Bible’s answer
Regarding his record of the events in Jesus’ life, the apostle John wrote: “He that has seen it has borne witness, and his witness is true, and that man knows he tells true things, in order that you also may believe.”—John 19:35.
One reason to trust the Gospel accounts recorded by Matthew, Mark, Luke, and John is that they were written while many eyewitnesses to the events they describe were still alive. According to some sources, the Gospel of Matthew was written as early as the eighth year after Christ’s death, that is, about 41 C.E. Many scholars favor a somewhat later date, but there is general agreement that all the books of the Christian Greek Scriptures were written during the first century C.E.
People who saw Jesus while he was alive on earth, witnessed his death, and observed his resurrection could verify the Gospel accounts. They could also easily expose any inaccuracies if there had been such. Professor F. F. Bruce observes: “One of the strong points in the original apostolic preaching is the confident appeal to the knowledge of the hearers; they not only said, ‘We are witnesses of these things,’ but also, ‘As you yourselves also know’ (Acts 2:22).”