The Apostles wondered (Luke 9:43b) at what Jesus had done and asked him why they couldn’t heal the boy (Mark 9:28; Matthew 17:32). At that time Jesus told the disciples that they needed to keep in mind that he would be turned over to his enemies and would be killed (Luke 9:44), but they simply were unable to understand what he was saying, because what Jesus meant was hid from them (Luke 9:45). The problem is that the rabbis taught that the Messiah would come and successfully free the Jews from those who enslaved them (the Romans in the context of the first century AD).
All practicing Jews believed that doctrine (cf. John 12:34). Nevertheless, the doctrine is completely false. If one believes a great leader will arise and lead the people to victory over their enemies, how would they who hold this belief comprehend the teaching that this same great leader would be killed by his enemies? Where’s the victory according to the doctrine the Jews believed? Jesus’ teaching simply had no place in such a worldview, and that worldview / understanding hid the truth from them.
No one who holds something to be true really believes he is wrong. That one perceives everything in the context of that doctrine, whether such a teaching is true or false. If the doctrine one holds to be true is false, whatever one perceives that arises out of that belief could never be true. Jesus’ disciples were afraid to ask Jesus about the statement he made about his death, because they were afraid it would be true, and , if so, how could he be the Messiah. They didn’t want to believe such a thing, so all the more they wanted the rabbis’ doctrine of an immortal Messiah to be true. Certainly, the Apostles understood Jesus was challenging what they believed, otherwise, why would Peter have earlier taken Jesus aside to inform him that he must be incorrect to say the Messiah would be taken by his enemies and killed (cf. Matthew 16:21-22)?
We are often challenged today by folks who claim the Bible isn’t true, and by folks who come claiming the Bible is true but teach contrary to the Bible. This can be good or evil, as far as our spiritual development is concerned. On the one hand a challenge can strengthen one’s faith and encourage one’s walk with Christ, especially as the disciple recognizes he is able to withstand the darts of the enemy.
On the other hand, if we are overcome by what challenges us, then it will affect us in an evil manner, like Jesus’ disciples who couldn’t understand what he said. Such believers have trouble understanding even that which the word of God clearly claims. The disciples shouldn’t have had any trouble understanding Jesus when he claimed he would be taken and be killed. He was very clear on that point, but they not only embraced a false and contradictory doctrine, but they preferred what is false to the truth, so the truth had no place in their worldview on that matter. So it will be concerning anyone who embraces a false doctrine.
It seems clear that Luke’s purpose, in recording the condition of the young boy (Luke 9:37-45) immediately after Jesus’ Transfiguration, is to make a contrast between the two conditions. The physical phenomena that occurred from within the young boy (Luke 9:39), has a spiritual similarity with the teaching of men who teach in Jesus’ name, but aren’t his disciples (Jude 1:4, 13). Their teaching is like the foam coming from the mouth of the young boy.
The certain men of Jude 1:4 do what they do out of greed for reward—money or power (Jude 1:11). According to Colossians 3:5, the covetousness of certain men (e.g. of Jude 1:4, 11) shows they are idolatrous. These men were compelled by their inordinate desire for reward (Jude 1:11) to teach lies for the purpose of gathering disciples after themselves. In so doing, believers were held by a different spirit and embraced a different gospel concerning a different savior (2Corinthians 11:3-4, 13-15).
If Jesus’ Transfiguration is a figure of our own metamorphosis (Romans 12:2; 2Corinthians 3:18), then its contrast with Luke 9:39, in the light of its spiritual manifestation in Jude 1:13, unveils for us the method of God in contrast to the method of the world to change mankind. God changes man from within, helping mankind to desire to change into what God wants him to be (Romans 12:2; 2Corinthians 3:18). On the other hand the world’s method hold’s mankind captive by a seducing spirit (of error) in an effort to compel men to be as the world leaders desire them to be (Jude 1:11; 2Corinthians 11:3-4, 13-15).