One of his many miracles recorded in the Bible:

The resurrection of the daughter of Jairus

And when Jesus came into the ruler's house, and saw the minstrels and the people making a noise, He said unto them, Give place: for the maid is not dead, but sleepeth. And they laughed him to scorn. But when the people were put forth, he went in, and took her by the hand, and the maid arose. And the fame hereof went abroad into all that land. Matthew 9:23-26 KJV

Those that laughed at Jesus were sent away. They did not see the moment the girl came back to life. They only heard about it or saw the result of the miracle later, and then they could come to their own conclusion: Did Jesus resurrect the girl from the dead, or as Jesus had said, was she only sleeping?

The faithless do not see miracles because God's love is protecting their free will. He wants everyone to achieve ultimate happiness, which requires freedom, and not a forced belief. Someone with no faith that sees Jesus perform a miracle would be compelled to believe in him, and that faith would be dead, not living. Only a man who voluntarily comes to Jesus will have a living faith. And he shall see miracles!