The power that Jesus had was not limited. More than that he had the authority to carry out the works he did. Nowhere was both his power and authority more apparent than when dealing with demons.
There were numerous times when the Lord cast out demons from people afflicted in this way. In each case the demons were removed and cowered in the presence of the Lord. They did not fight him for he had the authority to deal with them and they simply had no choice but to obey his command and get out as they were told.
In this particular case the demon that was in this boy was particularly strong. He had overtaken the child causing convulsions, what appears to be epilepsy and foaming at the mouth. When the boy’s father brought the child to the disciples to have the demon cast out, they could not do it. Thus it was evident that this was a particularly nasty and strong demon.
Why could the disciples not cast out this demon? Jesus shows that in his response to them saying, “O faithless and perverse generation…” (Verse 41) Jesus shows that the reason they could not cast out this demon was due to a lack of faith and a perverse attitude.
Faithless is translated from the Greek word “apistos.” It can also be rendered as disbelieving, which gives it a slightly different emphasis. To disbelieve something is a little different to unbelief, which is what is often thought when someone is said to be faithless. Unbelief means they “do not” believe, but disbelief means they “cannot” believe. Something that appears so incredible that it cannot be believed is disbelief. The disciples could not believe that they had the power and authority over demons especially when they came up against a strong devil like this one. Their faith failed them and they fell into disbelief and therefore were unable to exercise the power and authority necessary to cast the demon out. It was as if it were too great a thing for them to do.
As for the word “perverse” which is translated form the Greek word “diastrepho,” this too has an interesting meaning. The word can also be rendered as distort, misinterpret and corrupt. From this I believe the disciples belief was distorted to the point that they could not exercise the power and authority Jesus had given them.
Put these two aspects together and we get a few possible different pictures of why they were unable to cast out the demon. The disciples were either puffed up with their own self-opinion because they had this power and thus had a distorted view of the power that they had and so failed in their attempts to heal the boy. Or they may have been in awe of the power and in disbelief did not believe they could possibly be strong enough to do this work. Their view was thus distorted or corrupt and the lacked the faith to carry through.
There are other scriptures that could back up these possible scenarios. Consider the following which suggests they may have had a high opinion of this power the Lord had given and thus their focus was on the wrong things, which Jesus then rectified.
“17 The seventy returned with joy, saying, “Lord, even the demons are subject to us in your name!”
18 And he said to them, “I saw Satan fall like lightning from heaven.
19 Behold, I have given you authority to tread upon serpents and scorpions, and over all the power of the enemy; and nothing shall hurt you.
20 Nevertheless do not rejoice in this, that the spirits are subject to you; but rejoice that your names are written in heaven.” (Luke 10:17-20)
The Lord gave them the power to do these works so that they could release the people from all forms of bondage as they spread the gospel. The power also bore testimony to the truth of the gospel, just as the miracles and healing Jesus did bore witness to the message he gave to the people.
Naturally when the demon came up against Jesus it knew the gig was up. He had a last fling at hurting the boy, but it was fruitless for unlike the disciples who in their weaknes and lack of faith could not deal with the demon, Jesus was the Son of God and all powerful. The demon’s number was up and it knew it.