Mark 5:8

For he said unto him, Come out of the man, thou unclean spirit.

Jesus spoke directly to the unclean spirit tormenting the possessed men at Gadara, commanding it to come out and displaying His supreme authority as the Prince of Light over Satan and the powers of darkness.
His calm word pierced their darkened minds so that even while the demons resisted through them, the men dimly sensed One near who could save them and fell helpless at His feet seeking mercy.
The demons could not resist His command but obeyed and released their victims, so their madness ended and they were restored to reason, calmness, soundness of mind, and worship.
Their deliverance proves the gospel is a living power that transforms souls degraded into instruments of Satan into messengers of righteousness.
Though Satan meant the destruction of the swine to turn the people away, God overruled it for good, leaving the healed men as witnesses whose testimony throughout Decapolis opened the door for thousands to flock to Christ when He returned.

Christ Commands Unclean Spirits

The command belongs to the healing of the demon-possessed men at Gadara, where two men were tormented by the spirits, and it took place just before Jesus returned and was met by Jairus asking for his dying daughter.

Jesus exercised calm, divine authority and did not flee before the possessed men but stopped their advance with His raised hand so they could come no nearer and stood raging but helpless before Him. His spoken command for the spirits to come out penetrated their darkened minds enough for the afflicted men to dimly realize One was near who could save them from the demons tormenting them, so they fell at His feet worshiping Him and seeking mercy even while the demons spoke through them to resist Him.

By directly commanding the unclean spirit to come out, Jesus displayed authority over evil spirits and supremacy over Satan as the Prince of Light over the Prince of Darkness, and the demons were unable to resist Him but obeyed and released their victims. The spirits are intelligent, distinct, numerous and cruel agents of Satan, and a legion of them can torment one person, displaying Satan's power, cruelty and destructive control.

At His command the men were freed from torment and Satan's bondage, their madness ended, and they were restored to reason, calmness, soundness of mind and gentle appearance, sitting and listening to Him, worshiping Him and praising God. The demons were driven from their human dwelling and entered the swine, which rushed to destruction, exposing their destructive power over people and animals, while Christ's restraint preserved the swine's keepers and owners and the delivered men found safety in His presence.

Deliverance Becomes Witness

The men freed at Gadara became witnesses to His saving power, and their deliverance leads them to serve by sharing that good news with others. Freed from demonic power by His direct command to the unclean spirit to leave, they told their households and neighbors and the people throughout Decapolis what He had done for them. They became messengers of His saving power and witnesses that He is the Son of God, telling others what they themselves had seen and heard and felt of the Saviour's power.

Their deliverance proves the gospel is a living force to change the life, transforming souls degraded into instruments of Satan into messengers of righteousness. Though they heard His words only a short time and never heard a sermon from Him, they could witness to what grace had touched in them, and this is the witness every touched heart is called to give. God freely accepts even those whose course was most offensive when they repent, imparts His divine Spirit, sends them into the camp of the disloyal to proclaim His mercy, gives Christlikeness of character and assurance of His great love, and will not be satisfied until all who will accept salvation are reclaimed and reinstated as His sons and daughters.

The working of evil is overruled for good, for even the power of demons is under the control of the Saviour. Satan's purpose in the destruction of the swine to turn the people away and prevent the gospel in that region only roused the whole country and directed attention to Christ. Though Jesus Himself departed, the men He healed remained as witnesses to His power, changed from mediums of the prince of darkness into channels of light and messengers of the Son of God. Through them a door was opened to the gospel throughout that region, so that when Jesus returned to Decapolis thousands from all the surrounding country flocked to Him and for three days heard the message of salvation.

The deliverance shows His mercy in restoring the afflicted to reason, while the Gadarenes' response warns that fear of worldly loss can lead people to reject Christ and drive His Spirit from their hearts. Jesus casts out demons by speaking, and His word is a manifestation of God's Word and a source of power. The same demon possession seen in the man who tore and cut himself until the devils were cast out holds a person who gives soul, body, and spirit to Satan in order to rule another person's mind and body.