How do we know Christ has the power to heal and redeem?

In Mark 5, when Jesus encounters the man possessed by a legion of demons, His command to the unclean spirits to come out demonstrates His absolute authority over evil. The transformation of the man from despair to being in his 'right mind' exemplifies that only Christ can bring true healing and restoration. It showcases the sovereign grace of God that not only heals physical ailments but also frees individuals spiritually from sin and condemnation. Moreover, this passage affirms that Jesus, as the God-man, came specifically to destroy the works of the devil and set free those who are captives.