You're taking scripture verses out of context. Jesus was talking to a man who asked to be healed.

(Mark 9:22-25 NIV) "It has often thrown him into fire or water to kill him. But if you can do anything, take pity on us and help us." {23} "'If you can'?" said Jesus. "Everything is possible for him who believes." {24} Immediately the boy's father exclaimed, "I do believe; help me overcome my unbelief!" {25} When Jesus saw that a crowd was running to the scene, he rebuked the evil spirit. "You deaf and mute spirit," he said, "I command you, come out of him and never enter him again."

(Acts 14:9-10 NIV) He listened to Paul as he was speaking. Paul looked directly at him, saw that he had faith to be healed {10} and called out, "Stand up on your feet!" At that, the man jumped up and began to walk.

In some cases the person to be healed had to have enough faith. But miracles don't happen like that today. The dead aren't raised. The blind don't receive their sight. And so on.