But as we live in a world full of liars and scam artists it is wise to question the validity of such claims. How do we know that those miracles occurred or could they have been fabricated? While the miracles affirm Jesus, what would God have done to affirm that the miracles themselves actually occurred in history? Afterall, the nature of miracles is that they occur at some point in time after which they are history. Thus God would have had to deal with the issue of "historical evidence." While some may want, or even demand, that they themselves witness a miracle before they believe, that may be sufficient for them, but is it really necessary? And if God were doing miracles all the time, then would they even be considered miracles but rather natural occurrences - like the "miracle" of life?
Now in establishing historical fact, the testimony of others should not be discounted. And Jesus also affirmed relying on the testimony of others concerning his miraculous resurrection from the dead, "Blessed are those who have not seen and yet have believed." John 20:29 As for historical evidence, consider the types of miracles alluded to, their public nature, and the fact that his enemies could have easily destroyed his reputation if such miracles hadn't occurred.
For example according to John 9 Jesus publically healed a well known beggar born blind from birth. The beggar himself went on to debate the religious leaders in a public forum. How would you fabricate such an account? At best you'd have to simply make up the story - there having been no such person - and hope no one checks out the facts. But as with all Jesus' miracles such accounts would come under the skepticism of the religious leadership who put Jesus to death. Since they are allegedly in the story they would have been able to testify against this account if it had not occurred.If the apostles tried to fabricate these accounts, first of all there's no way they would have gotten away with it. Everyone would have know they were lying - especially their enemies. Their enemies - the ones who put Jesus to death - were the leaders of the society. They could have easily stopped Christianity at its outset by simply pointing out the lies. If there had been a conspiracy among the apostles to fabricate stories, they would not have even alleged such miracles to have occurred in public subject to critique by their enemies. Nor would they have alleged there being so many of them. And what would they have gained? By lying they would have known they were contradicting the very message they were preaching.
This is typical of Jesus' miracles. In John 5 he heals a man lame for 38 years publically known, and again there was an encounter with the Pharisees. They never denied these kinds of miracles, but rather "because Jesus was doing these things on the Sabbath, the Jews persecuted him." John 5:16
So also he made bread and fish appear out of nowhere in his feeding of the 5000 and then the 4000. He raise a man from that dead after he had been buried for three days, as well as raising others from the dead. He healed multitudes of the lame, blind, deaf, and demon-possessed.
Consider Peter's sermon of Acts 2. It was first of all alleged that on the day of Pentecost "there were staying in Jerusalem God-fearing Jews from every nation under heaven." Acts 2:5 That's believable as was typical of such celebrations under the Law of Moses. Then it was alleged that Peter spoke to the crowds. Among the things he allegedly said was, "Men of Israel, listen to this: Jesus of Nazareth was a man accredited by God to you by miracles, wonders and signs, which God did among you through him, as you yourselves know." Acts 2:22 He went on to speak of the death and resurrection of Christ, and 3000 Jews allegedly repented and were baptized that day - another 5000 shortly afterwards in Acts 4.
Jews all over the Roman Empire could have affirmed whether or not this event had occurred. This was an international event. Furthermore if this event hadn't occurred, then where did Christians first come from? People all over the world would have know whether or not thousands of Jews were baptized that day. This kind of account is virtually impossible to fabricate. Now consider the message Peter spoke, for in it he said that Jesus did miracles and that they knew that fact. Now if Peter was lying and Jesus didn't do miracles, the people would not have listened to him and gotten baptized, as they would have known that he was lying.
These are the kinds of historical facts which provide convincing evidence that Jesus historically performed miracles which "are written that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in his name." John 20:31