'Mighty' in the Bible

When the Sabbath had come, he began to teach in the synagogue, and many hearing him were astonished, saying, "Where did this man get these things?" and, "What is the wisdom that is given to this man, that such mighty works come about by his hands?

He could do no mighty work there, except that he laid his hands on a few sick people, and healed them.

But Jesus said, "Don't forbid him, for there is no one who will do a mighty work in my name, and be able quickly to speak evil of me.