This is shown by the experience of the converted Simon in Acts 8. He was so impressed with the outward manifestations of the Holy Spirit's power, that he wanted to be able to do those things too, and even offered Peter money to have the gift of imparting the Holy Spirit, for which Peter rebuked him severely. This is the error of extreme Pentecostal groups. Miracles, visions, exorcisms, and other demonstrations of the power of God over evil may happen, as God sovereignly chooses, especially in the establishment of a great new era, like the coming of the gospel to the Samaritans. But the bible clearly shows that those things only point to the real power.
Miracles have no power in themselves to make people believe.
Let me say it again. People will not believe because they see miracles. We don't need them. In the case of Samaria, the text says that when the crowds saw the miraculous signs Philip did, they all paid close attention to what he said. That's the most miracles can do - get people's attention so they'll listen to the gospel.