"So Jesus came again into Cana of Galilee, where He made the water wine. And there was a certain nobleman, whose son was sick at Capernaum. When he heard that Jesus had come out unto Galilee, he went unto him that He would come down, and heal his son: for he was at the point of death. Then said Jesus unto him, except ye see signs and wonders, ye will not believe." John 4:46-48
You almost can't blame the man looking to Jesus for a miracle. His son was dying and he was desperate. He did have the faith within himself to know that Jesus could perform the miracle and Jesus did perform the miracle. Jesus didn't even go, He just spoke the word and the man's son was healed.
The statement that Jesus made, "except ye see signs and wonders, ye will not believe," was a statement about the condition of the people in Israel (God's chosen people) and the people outside Israel as well; a statement about what they had become over time. They had become a people of 'show me and I'll believe.' They had become a works based society. Their leaders, the Sanhedrin and the Pharisees who were overseeing/handling the faith of the nation has turned from God's ways and made a new set of rules for themselves.
Over time they dismissed the miracles of the 'freedom from slavery of Egypt' generation and the 'crossing of the Red Sea' generation and the 'wandering in the wilderness' generation, and the 'fed with manna' generation. They had killed off the prophets and they were bent on having an Israel with a worldly leader, someone magnificent and full of splendor, someone who would destroy the Romans and bring glory to Israel like never before. They missed the coming of the Saviour and now they had a reputation to uphold, proud, strong men, men who needed a sign or personally witness a miracle or else they would hold to what is sure, their place in the temple. They had become so enamoured with the temple, they forgot the God who once inhabited it. They were bent on creating for themselves a place of acceptance by the Romans. They had become slaves again, but this time of their own doing.
The Saviour of the world had come among them and they were either rushing toward Jesus like a kid watching a parade, hoping to get a piece of candy thrown their way or they were ignoring His presence altogether as that of a charlatan. Jesus' message was not enough for the hardened of heart. Many of them had already made up their mind that even if this was the Saviour, they would kill him, because he threatened their current religious system. But more than that the hardened of heart had reduced Jesus to a man who practiced legerdemain. Jesus knew their hearts and that is why He could say, "except ye see signs and wonders, ye will not believe."
Is it really that different today? Tens of thousands of people go to single stadium events just to see someone perform a miracle. Except they see it with their own eyes they will not believe. And even if they see it with their own eyes they still are only giving mental assent that what they saw was true or real. While godly men and women are talking to atheists or agnostics about faith, they say that they will believe if God was to come down and strike them dead or something like that. I've heard it too many times. Just show me a sign and I will believe. But I don't think so.
Even in the story of Lazarus and the rich man Jesus confirms Abraham's words, "If they will not hear Moses and the prophets, neither will they be persuaded, though one rose from the dead." I hate to be the bearer of bad news, but the unbelieving world is under a strong delusion. It is very likely that they would not admit that Jesus is Lord even if they personally witnessed ten miracles in a row. They already deny the miracle of life and they already deny the miracle of creation and they especially stand against the miracle of faith.
Don't be discouraged if you have never seen a miracle of witnessed some wonder performed by Michael or Gabriel. It is your faith that has saved you and healed you and brought you this far and it is your faith that will take you all the way home. Jesus make it pretty clear how it really works. "Thomas, because thou hast seen Me, thou hast believed: blessed are they that have not seen, and yet have believed." John 20:29b
Faith enters through the mind and resides in the inner man. Faith comes when you hear God calling you and you answer yes. Faith is the visible proof of an invisible work. You need not that God ever prove Himself if you have even the tiniest faith. But without faith, mountains could be moved out of your way, riches spilled throughout your house, talents lavished on you without reserve, love at your side, a healed body over and over again, life's best at your fingertips and you can't see any of it, because blindness due to faithlessness is total blindness and there is no cure except faith.