Originally Posted by
Colonel
The above account was just an example. There is also "this type doesn't leave without prayer and fasting". The word fasting isn't there in the earliest manuscripts but the word prayer is in one of the accounts which makes that part sure. I think that has to do with the connection between the person and the demons. Meaning that it's not useful to cast out the demon until the person is ready because the person will let the demon(s) back in again. Which requires prayer in the broader sense which also includes praying together, counselling etc. Attempting to cast out the demon without those things might result in a struggle where the person struggles along with the demon rather than against the demon. Which is something that one would like to avoid.
I've also seen demons leave people a few times without any command being spoken, just the presence of God combined with a general change in the person's heart.
Acts 19:12 so that even handkerchiefs or aprons were brought from his body to the sick, and the diseases left them and the evil spirits went out of them.
In this verse, the presence or power of God went from the handkerchiefs and aprons and the evil spirits simply left.
I've also seen people ask their demons to leave because they had been convinced of the truthfulness of the gospel at a point where they already knew very well the content of the gospel.