There is no denying that the Christian community played its part between Jesus and the writing of the Gospel, for example, the variations in the different versions of recording the Lord’s Prayer in Mt 6:9-13 and Lk 11:2-4). This is why scholars have sought criteria to be able to come as close as possible to Jesus’ actual words, but no criterion is absolute and some are easy to criticize.
Main criteria
Criterion of Embarrassment and Contradiction
The test can be formulated as follows: Would the early Church have created manuscripts putting her in an awkward position or weakening her position in discussions with opponents? The most obvious example is Jesus’ baptism, whereas He is considered sinless and greater than John the Baptist who preached a “baptism of repentance for the forgiveness of sins.”
Criterion of Discontinuity
This criterion is formulated as follows: “Everything that is not in accordance with the trends of the environment (Hebrew before Jesus and Christians after Jesus) is certainly from Jesus.” For example: in the Greek and Palestinian world of that time, it was the disciple who chose the teacher. Jesus does exactly the opposite: He chose the group of twelve (Mk 1:16-20; Mt 4:18-19; Lk 5:1-11). This could not have been fabricated. Another example is the use of "amen" as the introduction of speech, rather than as a conclusion or final word."Amen", in fact, amounted to a “yes” or a good wish (responsive and desiderative expression).
Multiple Attesting Criterion
Multiple attesting consists in the discovery of a component that exists in several different traditions (Mark, unique traditions of Matthew Luke, John, Paul, and so on) or in several literary forms (parables, disputes, aphorism, prophecies, miracles ...). For example, that Jesus had in one way or another talked about the kingdom of God or the kingdom of Heaven is widely attested in the Synoptics and in John and Paul, as well as in various literary genres, parables, the Beatitudes, prayers, aphorisms, etc. Other examples are Jesus’ words about the bread and wine at the Last Supper (Mk 14: 22-25; 1 Cor 11: 23-26; cf Jn 6: 51-58), contesting easy divorce (Mk 10: 11-12; Lk 16: 18; 1 Cor 7: 10-11) and the purification in the temple (Mk 13: 2; 14:58; Jn 2:14-22).
But there are some isolated phrases that have a high probability of having been pronounced by Jesus Himself, along with the invocation “Abba”, the two “Effatha” imperatives and “Talithà qum”. So this argument proves that this test has its limits.
Criterion of Coherence
This criterion implies the existence of the previous criteria, on which it depends: the fact that words and gestures are coherent with what has been clearly attested has a good chance of being historic.
Criterion of Refusal and Execution
It is necessary to determine what words or deeds of Jesus caused His violent death and crucifixion as "King of the Jews".
Secondary Criteria
Criterion of Semitisms
According to this criterion, if Jesus’ words are typical Aramaic because of the vocabulary, grammar, syntax, rhythm and the rhyme present in the current Greek versions, it would be a sign of their authenticity. But it is difficult to say that a word in an elegant Greek text was not spoken by Jesus if the translator had a functional rather than a literal purpose and vice versa. The modern philological current thinks that the “Semitisms” might not be authentic.
Criterion of a Lively Narrative:
This criterion cherished by Taylor has been particularly applied to Mark--the liveliness and abundance of concrete details are good indicators of a report made by eyewitnesses and a sign of high historical value. The objection is that one can add vibrancy to any story, non-fiction or fiction. In the same way that liveliness is not a criterion in speaking about historicity, a narrative reduced to the essential does not mean it is not historic.
Criterion of Synoptic Tradition:
The formalist school works by following this principle: the synoptic tradition develops from Mark to Matthew and to Luke, as they have the tendency to use more concrete details, add names to narrators, eliminate semitisms… The fault in this criterion is that you can’t establish fixed rules for the development of synoptic tradition and then apply them to primitive oral tradition.
Criterion of Historical Presumption:
Does the burden of proof fall on the one who denies historical authenticity or on the one who affirms it? Some argue that those who want to isolate a word or authentic action of Jesus must show it; others, since ancient writings give credit to the facts and since the eyewitnesses of Jesus were the leaders of the primitive community, say just the opposite, i.e. that the burden of proof is on those who discredit a word or a story.