It's easy to look back & shake our heads at the original 12 Apostles.
They sure look like a buncha thundering asshats, don't they?
Of course, they didn't have two millennia of heavily ingrained cultural / historical / theological indoctrination backing them up. They were getting all of Jesus' teachings fresh from the mouth of the Master, and their only point of reference was the very culture of corruption & hypocrisy He had come to replace.
Matthew, Mark, and Luke all report a key friction point among the 12 Apostles, namely John and his brother James jockeying for position as Christ's right-and-left-hand men in Kingdom Come. John, in his Gospel, omits this embarrassing detail; however he refers to himself as "the beloved disciple" indicating a closer personal relationship with Jesus than the others.
After the resurrection the petty jealousy & internal bickering still persisted, viz, Simon Peter asking Jesus about John (it wasn't until Pentecost that the Holy Spirit finally imbued the disciples and put an end to much of the personality squabbles).
As I said, we today have the advantage of 2,000 years of culturally ingrained knowledge: Even non-Christians have absorbed much of the Gospel story through sheer osmosis.
We’ve been exposed to spoilers, to use common parlance.
Jesus’ first century audience -- in particular His disciples -- didn’t know any of what is cultural common knowledge today.
The 12 Apostles, Judas Iscariot included, all believed they were in the presence of a mighty man of God, more specifically the long-awaited Messiah.
But as to who He really was
Reading the Gospels, it’s clear the Twelve anticipated an earthly kingdom that they would participate in.
They had reason to believe this: The crowds were on their side, Jesus was gaining popularity wherever He went, even the Pharisees couldn’t match him in theological debates.
And as pointed out in Parts 1 & 2, the Pharisees -- in particular Annas & Caiaphas’ clique -- were in very real danger of getting swept out of office by Pontius Pilate if he felt the new preacher from the sticks would help keep the peace in Judea. So they concocted the lie that He was stirring up the people to rebellion, that He would rouse Roman ire by proclaiming Himself a king, and that all of Judea would suffer because of this, so it was better if they just railroaded him on the spot, not for their sakes -- heavens, no! -- but for all the poor, innocent potential victims.
So basically everybody regarded Jesus as a contemporary political hero -- except Jesus!
He knew there were much bigger issues at stake, but His disciples couldn’t wrap their minds around that.
So He had to put up with a lot of silly, stupid, petty bickering in His ministry. James & John wanted to be big kahunas, the other 10 got their tunics in a twist over this.
Remember how in jr hi there was that one person you really really rilly had a major league crush on? And how you really really rilly wanted to go to the dance with ‘em?
And how they went with somebody else?
And how you hated them and despised them and you’d show them by writing terrible things about them and telling everybody how awful they were and you’d spoil their chances of getting elected to the student body and -- and -- and --
…and I wonder if that’s where Judas’ head was at when he sold out Jesus for 30 pieces of silver.
I don’t necessarily think Judas had any idea where all this was going to end up. He may have anticipated an arrest, some jail time, certainly Jesus getting bumped off the short list of potential High Priest candidates…
…but to actually be killed? Crucified? I dunno, maybe Judas didn’t see that one coming. Maybe Caiaphas et al didn’t see it coming, either. Maybe all of them expected Pilate to say, “You have got to be kidding me!” and chuck the lot of them out.
But it didn’t happened.
It happened that Jesus was crucified and killed, that He was buried, and that everyone thought that was the end of the matter.
 No duh!
 He and his brother are referred to as "sons of thunder" which implies strong oratory skills, which could indicate a more formal theological training, which could mean they were spiritually more closely attuned to what Jesus was doing than Simon Peter and the other disciples; the text of the Gospel of John focuses more on the divine nature of Christ than the Synoptic Gospels.
 But not all of it, alas...
 Truth be told, there were a lotta guys in the Messiah business between the Maccabee revolt in 167BC and the fall of Jerusalem in 72AD. Even this guy --
-- was considered a messiah by the Jews held captive in Babylon since he released them from their bondage & allowed them to return to rebuild Jerusalem. In major cities around the world today you can find billboards & advertisements for local rabbis who are touted as messiahs by their congregation.
 A pretty neat trick, considering how the steam locomotive wasn’t invented for another 17 centuries…
 Oh, yeah, John accuses Judas, the band’s treasurer, of having sticky fingers, but as we’ve seen above, John is not the most unbiased of narrators. He was too embarrassed to ‘fess up to trying to worm his way into a top dog position, he might have been too embarrassed to admit to anyone, even himself, that his actions might have contributed in any way to Judas’ betrayal & Jesus’ death. In that case, he probably wanted to dredge up every detail, no matter how trivial, that might make Judas look like evil incarnate.