Hello Christians
i was talking to an agnostic who left Christianity because of there's no proof for the existence of Jesus outside the bible
Well, as an agnostic, perhaps I can provide some counters to what the person you spoke with said.
First, it's important to understand that when people use the term "proof" in relation to history they are typically applying something like the legal term. The problem with this is that historians can use any and all information available to them and that it is they, as experts, who weigh it (unlike in courts, where an untrained jury would). As a result, frequently historians come closer to "proof", or at least do not have many of the obstacles present in courts. In general, proof is for mathematics and eve the sciences do not use the term to describe the confirmatory results of experiments.
Second, it is true there isn't a great deal of evidence outside of the New Testament for Jesus. That doesn't mean there is none, nor that none of it is important. A fairly exhaustive list would include:
Josephus, Tacitus, Suetonius, Pliny the Younger, Mara bar Serapion, Lucian of Samosata, the Talmud, Celsus, Papias, & Thallos. Of these, there is no question that Josephus is, taken singularly, the best non-biblical source. Some of the others are questionable at best. If pressed, I'd say that Josephus, Tacitus, and Papias are the only ones who provide by themselves at least some reliable confirmation of Jesus' existence.
Third, it is important to realize that although the gospels are religious documents, that doesn't preclude them from being forms of ancient history. In actuality, we have more evidence for the historical person of Jesus than virtually anybody from in and around his day, including important aristocrats. If you are interested in learning why historians regard the gospels as at worst containing historical accounts and at best as biographies, I would be more than happy to direct you to sources or answer any questions.
Fourth, it's important to avoid treating sources in isolation. For example, Paul mentions in passing that, while staying with Peter, he also saw Jesus' brother James. The gospels also state the Jesus had a brother named James and even more importantly, so did the non-Christian Jewish historian Josephus. It's kind of hard to have a brother without existing.
she considered his existence as a myth specially that his birth, life and resurrection are identical to Krishna, Mithra and Horus
Almost without exception, the stories about other dying and resurrecting gods are modern inventions. The Persian Mitra had nothing in common with Jesus. Mithras, the deity worshipped in the Roman mystery religions, was like Jesus in that Mithras was a savior deity, but not only did he not die and then resurrect, this cult didn't exist until after most of not all of the NT had been written. Same with Attis. As for most of the others, like Horus and Krishna, what you will find (mostly online) about similarities is simply factually incorrect.
do you have any historical documents about the life of Jesus outside the bible
Thallos' writings have not survived but he is quoted by Julius Africanus.
Josephus mentions Jesus twice in his
Antiquities of the Jews, once in a passage that most scholars believe to have been edited, but also believe did originally refer to Jesus. In the other reference, Jesus is mentioned in passing to identify (kinship identification) the main person of interest: Jesus' brother James.
Pliny does not mention Jesus but refers to Christians in his letters to Trajan.
Tacitus refers to Christians to in his description of Nero and the first, but he also mentions that they are called Christians because of whom they follow: Christ. He also mentions that this Christ was executed by Pilate.
In his
Lives of the Caesars Suetonius mentions the expulsion of Jews from Rome because of their disturbances. He notes that these were instigated by a certain "Chrestus" which may refer to Christ but we can't know.
In a passionate letter to his son, Mara bar Serapion lists a number of tragic events and among them that the Jews killed "their wise king" (Jesus, as a messianic claimant, certainly seems to have caused others to believe he was claiming kingship).
Lucian likewise mentions the execution of someone who appears to be Jesus given the description, but we can't know.
More promising is Celsus, an anti-Christian whose work survives in extensive quotation by Origen. Although it is late, Celsus tells us of rumors regarding Jesus that are in no Christian tradition. Give the nature rumors and Celsus' anti-Christian stance, had anybody ever thought that Jesus didn't exist it, it seems likely that Celsus would have used such rumors. He did not, and neither did anybody else (Christian or no).
Finally, Papias' writing survive in part in part in the monumental history by Eusebius. Papias describes knowing those who either knew Jesus knew his disciples.
