How do we know that Jesus has authority over unclean spirits?

In Mark 1:25, Jesus rebukes the unclean spirit with the command 'Hold thy peace, and come out of him.' His ability to silence the spirit and command it to leave illustrates His divine authority. The reaction of the people, who were astonished by His teaching and the obedience of the spirits, further emphasizes that He possesses complete control over both the spiritual and natural realms. His commands carry the weight of divine authority, proving that even the forces of darkness must obey Him.