Fuller information about Jesus is found in the Gospels of the New Testament, though those are not of equal value in reconstructing his life and teaching. The Gospels of Matthew, Mark, and Luke agree so closely with one another that they can be studied together in parallel columns in a work called a synopsis and are hence called the Synoptic Gospels. John, however, is so different that it cannot be reconciled with the Synoptics except in very general ways (e.g., Jesus lived in Palestine, taught, healed, was crucified and raised). In the Synoptics Jesus’ public career appears to have lasted less than one year, since only one Passover is mentioned, but in John three Passovers occur, implying a ministry of more than two years. In all four Gospels Jesus performs miracles, especially healings, but, while exorcisms are prevalent in the Synoptics, there are none in John. The greatest differences, though, appear in the methods and content of Jesus’ teaching. In the Synoptic Gospels he speaks about the kingdom of God in short aphorisms and parables, making use of similes and figures of speech, many drawn from agricultural and village life. He seldom refers to himself, and, when asked for a “sign” to prove his authority, he refuses (Mark 8:11–12). In John, on the other hand, Jesus employs long metaphorical discourses, in which he himself is the main subject. His miracles are described as “signs” that support the authenticity of his claims.
Scholars have unanimously chosen the Synoptic Gospels’ version of Jesus’ teaching. The verdict on the miracles is the same, though less firmly held: in all probability Jesus was known as an exorcist, which resulted in the charge that he cast out demons by the prince of demons (Mark 3:22–27). The choice between the narrative outline of the Synoptics and that of John is less clear. Besides presenting a longer ministry than do the other Gospels, John also describes several trips to Jerusalem. Only one is mentioned in the Synoptics. Both outlines are plausible, but a ministry of more than two years leaves more questions unanswered than does one of a few months. It is generally accepted that Jesus and his disciples were itinerant, that they traveled around Galilee and its immediate environs and that Jesus taught and healed in various towns and villages as well as in the countryside and on the shore of the Sea of Galilee. But where did they spend their winters? Who supported them? None of the Gospels explains how they lived (though Luke 8:1–3 alludes to some female supporters), but the omission is even more glaring in John, where the longer ministry presumes the need for winter quarters, though none are mentioned. That and other considerations are not decisive, but the brief career of the Synoptic Gospels is slightly to be preferred.
The Synoptic Gospels, then, are the primary sources for knowledge of the historical Jesus. They are not, however, the equivalent of an academic biography of a recent historical figure. Instead, the Synoptic Gospels are theological documents that provide information the authors regarded as necessary for the religious development of the Christian communities in which they worked. The details of Jesus’ daily life are almost entirely lacking, as are such important features as his education, travel, and other developmental experiences. The characters on the whole are “flat”: emotions, motives, and personalities are seldom mentioned. There are nevertheless a few exceptions that show how little is actually known: Peter wavers (Matthew 14:28–31; Mark 14:66–72), James and John ask for preferential treatment in the coming kingdom (Mark 10:35–40), and Pilate anguishes over the decision to execute Jesus (Matthew 27:15–23; Luke 23:2–25). On the other hand, the Pharisees and scribes periodically challenge Jesus and then disappear, with little indication of what, from their point of view, they hoped to accomplish. Even Jesus is a rather flat character in the Gospels. He is sometimes angry and sometimes compassionate (Mark 3:5; 6:34, respectively), but one can say little more. This is a frustrating aspect of the Gospels. The situation is different with regard to Paul, whose letters are extant and self-revelatory. The force of his personality is in the letters, but the force of Jesus’ personality must be found somewhere behind the Gospels.
The Gospels comprise brief self-contained passages, or pericopēs (from the Greek word meaning “cut around”), relating to Jesus. Further study reveals that the authors of the Synoptic Gospels moved the pericopes around, altering the contexts to suit their own editorial policies—for example, by arranging the pericopes according to subject matter. In chapters 8 and 9, Matthew collects 10 healing pericopes, with a few other passages interspersed. Mark and Luke contain most of those passages, but their arrangements are different. Matthew put all those healings in one place, whereas Mark and Luke scattered them but in different ways. Since the authors of the Gospels rearranged the material to suit their own needs, it must be assumed that earlier Christian teachers had also organized stories about Jesus didactically. That means that the sequence of events in Jesus’ ministry is unknown.
Moreover, the Evangelists and other early Christian teachers also shaped the material about Jesus. During the course of transmission, the factual narrative elements that surrounded each saying or event were stripped away, leaving only a central unit, which was applied to various situations by the addition of new introductions and conclusions. For example, both Matthew and Luke relate the Parable of the Lost Sheep. In Matthew 18:12–14, the parable is told to the disciples, and the meaning is that they, like the shepherd, should go in search of the lost. In Luke 15:4–7 the same story is directed at the Pharisees, this time to instruct them not to grumble because Jesus has attracted repentant sinners. Both applications of the parable were useful homiletically and were therefore preserved. The context in which Jesus originally used the parable, however, is unknown. Another example is the saying “love your enemies” (Matthew 5:44). Homiletically, it may be applied to numerous circumstances, which makes it very useful for sermons and teaching. Historically, however, it is not known to whom Jesus referred when he spoke those words. The lack of firm knowledge of original context makes the precise interpretation of individual passages difficult.
Further, not all the sayings and deeds in the Synoptic Gospels are reports of things that Jesus actually said and did. Believing that Jesus still lived in heaven, the early Christians spoke to him in prayer and sometimes he answered (2 Corinthians 12:8–9; cf. 1 Corinthians 2:13). Those early Christians did not distinguish between “the historical Jesus” and “the heavenly Lord” as firmly as most modern people do, and some sayings heard in prayer almost certainly ended up in the Gospels as sayings uttered by Jesus during his lifetime.
Since both the original context of Jesus’ sayings and deeds and those passages in the Gospels that go back to the historical Jesus are unknown, there are substantial difficulties in attempting to reconstruct the Jesus of history. Of these two difficulties, the lack of immediate context is the more serious. It must be admitted that, on many points, precision and nuance in describing the teaching and ministry of Jesus cannot be achieved.
There are, however, tests of authenticity that make it possible to acquire good general information about Jesus’ teachings. One of the most important of these is “multiple attestation”: a passage that appears in two or more independent sources is likely to be authentic. A prime example is the prohibition of divorce, which appears in the letters of Paul and in two different forms in the Synoptic Gospels. The short form, which is focused on remarriage after divorce, is found in Matthew 5:31–32 and Luke 16:18. The long form, which is more absolute in prohibiting divorce, appears in Matthew 19:1–12 and Mark 10:1–12. Paul’s version (1 Corinthians 7:10–11) agrees most closely with the short form. Because of that excellent attestation, it is almost indisputable that Jesus opposed divorce and especially remarriage after divorce, though study of the five passages does not reveal precisely what he said.