During Christ's ministry he cast demons out of many. Let's look at two examples that the Holy Spirit has given to us as examples of what was typical.
The Demoniac of Gadara
In three of the Gospels we read of Christ and His disciples coming to Gadara by boat (Mt.8; Mk.5; Lk.8). Upon arriving there two men met Him who were "possessed of devils." Mark and Luke concentrate on the testimony of one of these men who came to be known as the Demonic of Gadara.
Previous to Christ delivering this man he had lived amongst the tombs since being possessed a "long time." At an early stage and on various occasions the demons would "catch him" (seize him). At those times, which were frequent, the local population would try to with strain him with "fetters and chains" but he simply broke them - this was not natural strength. Finally these demons drove him into the wilderness and mountains where he lived amongst the tombs. He lived in a state of nakedness, crying and cutting himself day and night. He was so "exceeding fierce" that none of the local people could pass by there.
Thank God that that was not the end of the story: "But when he saw Jesus afar off, he ran and worshipped him" (Mk.5:6). What a marvellous thing. A legion of demons could not keep this man from Christ. The very demons of Hell acknowledge the supremacy and sovereignty of Christ. i) They acknowledge that Jesus is the Son of the Most High God, ii) they acknowledge that their future punishment is torment, iii) and they acknowledge that Christ has the power to cast them totally out of an individual, without any reference to legal power or rights, and to free the man totally from their power.
When Jesus asked them what their name was they answered: "My name is Legion: for we are many." They then requested that they be cast into a herd of about 2000 swine which were nearby. Once He allowed them to go they "entered into" the pigs causing them to run "violently" down a step embankment into the sea drowning them all. The herders ran to the city and once they told the people what had happened almost the whole city and countryside went out to see.
"Then they went out to see what was done; and came to Jesus, and found the man, out of whom the devils were departed, sitting at the feet of Jesus, clothed, and in his right mind: and they were afraid" (Lk.8:35).
Here is one man who was indwelt by a legion of demons which could have been about 6000 demons in total. This would mean that just three in each of the pigs was enough to cause them to commit suicide. This man was no follower of Christ when possessed. But when Christ cast the demons out in one act in one moment all left and not one remained. The man was immediately set free from all demonic power. When the people came to see the man he was sitting at the feet of Jesus as a genuine follower and disciple of Christ. He was now in his right mind. And he was now clothed properly (meaning nakedness is demonically inspired).
The man wanted to stay with Christ but He told him to go home to his friends and to "shew how great things God hath done" unto him in having compassion upon him. The man returned home and began to "publish" ( to herald like a town crier) to the whole city "how great things Jesus had done unto him." Although just a new convert set free from 6000 demons there was nothing delicate or fragile about his salvation. Christ could send this lone witness back into his city to proclaim the goodness of God.
He needed no further deliverance ministry. It did not take weeks, months or years to expel the demons. Once the demons were expelled the man was translated into the kingdom of God and was a shinning testimony of freedom in Christ.
In Lk.8:2 we read of "Mary called Magdalene, out of whom went seven devils." And a little later we read in Mk.16:9 concerning her "out of whom [Christ] had cast seven devils." When she first appears on the scene of time this is her testimony and it is held forth until the time of Christ's death, burial and resurrection as a witness to His mighty delivering ministry.
The name "Mary Magdalene" was given to this little lady to distinguish her from the other Mary's mentioned in Scripture. She was from Magdala on the coast of Galilee. We are not told of the events, circumstances or reasons that led to her being possessed of seven demons but prior to her conversion those who knew her were very well aware that she was afflicted by demon power. It was evident, visible and known to all. Among those who were from Magdala none were so afflicted as her.
These seven demons were literally dwelling within her. Who can imagine what affliction and torment these seven devils caused her. Later it is revealed that she was a woman of "substance" (property or possessions - Lk.8:3). She had money but money could not help her against demon powers.
The fact of her deliverance from demon powers which Christ "cast out" out of her was a well known testimony in the early church. Please note that during those first years of her salvation her testimony does not change. It was always the "seven devils." Please note this number did not grow as she grew in Christ over the next two or three years. Christ cast seven demons out and no more. This was not progressive ministry over a few years. This was not an example of a Christian having demons cast out after her salvation. First she was delivered and then saved. Christ had to bind and cast out these strongmen before claiming her as His own.
All we read about after her conversion is her utter devotion to Christ. She was one of several woman who joined and travelled with the apostolic band which included Christ and the twelve disciples. She is mentioned fourteen times in the gospels. Eight of those times she is mentioned first when mentioned with other ladies. These ladies used their substance to finance this band of preachers who went forth preaching, teaching, healing and casting out demons. What hope and joy her testimony and witness must have brought to many oppressed souls. There is no talk of her still having demons or recieving such ministry while traveling with the apostolic band. No, she testified of a past deliverance which was never repeated.
With the Demonic of Gadara and Mary Magdalene we read of experiential testimonies which mention nothing of a ministry of deliverance after salvation - in fact the very opposite. We read of two people who once set free from demon power became shinning witnesses of freedom in Christ and zealous witnesses for Christ. These are the only experiential testimonies which carry weight for they are biblical ones given by the Holy Spirit and of course will be typical of thousands of others who Christ delivered in His ministry.