Mark 9:15 - When They Saw Jesus They Were Greatly Amazed

I am coming back to the transfiguration of Jesus  which was the subject of a previous post. The question is here is, why was the crowd "greatly amazed" when they saw Jesus after the transfiguration?   Here  is the account from  Gospel of Mark:

1] And he said to them, "Truly, I say to you, there are some standing here who will not taste death before they see that the kingdom of God has come with power."
[2] And after six days Jesus took with him Peter and James and John, and led them up a high mountain apart by themselves; and he was transfigured before them,
[3] and his garments became glistening, intensely white, as no fuller on earth could bleach them.
[4] And there appeared to them Eli'jah with Moses; and they were talking to Jesus.
[5] And Peter said to Jesus, "Master, it is well that we are here; let us make three booths, one for you and one for Moses and one for Eli'jah."
[6] For he did not know what to say, for they were exceedingly afraid.
[7] And a cloud overshadowed them, and a voice came out of the cloud, "This is my beloved Son; listen to him."
[8] And suddenly looking around they no longer saw any one with them but Jesus only.
[9] And as they were coming down the mountain, he charged them to tell no one what they had seen, until the Son of man should have risen from the dead.
[10] So they kept the matter to themselves, questioning what the rising from the dead meant.
[11] And they asked him, "Why do the scribes say that first Eli'jah must come?"
[12] And he said to them, "Eli'jah does come first to restore all things; and how is it written of the Son of man, that he should suffer many things and be treated with contempt?
[13] But I tell you that Eli'jah has come, and they did to him whatever they pleased, as it is written of him."
[14] And when they came to the disciples, they saw a great crowd about them, and scribes arguing with them.
[15] And immediately all the crowd, when they saw him, were greatly amazed, and ran up to him and greeted him. 
Mark 9:1-15 (RSV)

What is meant by verse 15 just quoted where it says, "when they saw him, were greatly amazed, and ran up to him and greeted him?"    Here is the explanation of Morna Hooker which you see quoted in Ardel B. Caneday's excellent blog.

[Mark] must mean that there was something about Jesus' appearance which gave them good reason to be astonished. The only possible explanation seems to be that Mark means us to understand that Jesus' appearance is still in some way affected by the transfiguration. If Moses, coming down the mountain after speaking with God, reflected the glory of God from his face without knowing it, and so caused all the people to be afraid (Exod. 34:29f.), it is not surprising if Jesus also, coming down the mountain from a similar experience, caused astonishment among the crowd. 
Morna Hooker, The Gospel According to Mark , 222-224  (as quoted by  Ardel B. Caneday  at ntexegesis.blogspot.com).

Caneday in his blog post just cited points out that "amazement" is the Greek word ekthambeō (ἐκθαμβέω), and he states further: 

In [Mark] 16:5 and 16:6, ekthambeō (ἐκθαμβέω) is used first of the women who came to the tomb and found it empty and were amazed, and then of the young man who had been seated at the right side of the tomb who cautions, "Do not be amazed!" The verb speaks of deep movement of emotions, particularly of trembling astonishment. Thus, in Mark 9:14, the verb ekthambeō(ἐκθαμβέω) bursts upon the reader with unexpectedness. Given the fact that Mark's other uses of the verb ekthambeō (ἐκθαμβέω) denote intense emotion, we would be amiss to devalue the verb's intensity in 9:14.
 http://ntexegesis.blogspot.com/2012/08/on-new-testament-use-of-old-testament.html

Interpreters like Hooker and others cited by Caneday are truly on the right track pointing out that Jesus' appearance "amazed" the crowd because his appearance was showing the effects of the transfiguration.  To catch that, the interpreter shows an openness and wonder that is one of the keys to our theological reading of the Bible.  Yes, we must do the literary and historical study of the texts, but here is a great example of the importance of coming to the text humbly hoping to see God.