Luke 4:36

‘And amazement came on all, and they spoke together, one with another, saying, “What is this word? For with authority and power he commands the unclean spirits, and they come out.”

What they had seen amazed the people who saw it. They had never seen anything like it. They knew of exorcisers who had various methods for trying to deal with evil spirits, including the use of incantations and formulae, and of various physical props, and the use of powerful names, but they had never come across One Who could get rid of them by a word on His own authority. They were astonished. They asked themselves what word this was that could force evil spirits to do its will. Why this man could command evil spirits with authority and power in such a way that they obeyed Him. Note the combination, He had the authority to command and the power to ensure that His command was carried out. We, of course, know the secret, He is the Lord's Anointed.