Hi, Jerome~

Thanks for your question.  Maybe I can shed some light on this verse.

I agree, at first it seems to be rather confusing.

But it helps to consider the entire passage (and even the entire Bible) when trying to understand what is being said here.

This is why we must be committed to studying on a daily basis in order to be infused with the Word of God. 

The more of the Word we have living inside us, the better we will be able to understand it...since Scripture interprets Scripture.

So lets give it a try...here goes:

In v.25 the people are asking each other, "Isn't He the one the rulers are trying to kill?"

Verse 26 shows that the people were amazed that Jesus was getting away with the things He was saying. 

...The people go on to be puzzled about the rulers, wondering if they really think that this is actually the Christ.  In other words, they are trying to figure out why the rulers are not responding to Jesus and shutting Him up, if they know He is an impostor.

v.27 The people wondering about this only think that they know where Jesus is from and they don't believe that He is really the Christ, because if He was the One true Christ, they think that no one would know where He came from.

Since they know his earthly origin, they think that settles it.

But in v.28, Jesus is saying, "Sure you know my earthly origin (what geographical area and family I have come from)...BUT...There is more to this than what you think...I am not speaking on my own...I was sent by One who is true...Someone you people don't know.

In other words, He is identifying God as the "one true God" and telling them that they are confused because they really don't know God.

Then He says in v.29 that He knows what He is talking about because He actually knows the One True God...in fact, it was this One True God (the Father) who sent Him (speaking of Himself, Jesus).

He is saying, "I know Him and He is the One who sent me."

Well, the people didn't like what He said because He was telling them that He knew God and they didn't and He was claiming to be the Christ they were waiting for.

... and in v.30, it says that when they heard Him say this, they got angry and wanted to take Him.

They wanted to believe that He was an impostor...not the real Christ that the Scriptures had said was coming.