repeat it again

No, it's not redundant. It stresses the repetition.

Thanks Mr. Marius Hancu

Abil "I have said it before. I will repeat it again that you allow us to complete the process.

I was taught that we cannot say 'repeat again' because 'again' is not required. However, Marius thinks it is fine. I'm confused. In fact, if I remember correctly, we've discussed this before.

Language is not mathematics, a lot of redundancy is built in the process, in order to make sure the right understanding is achieved.
See this in books:
91 on "will repeat it again that"

http://books.google.com/books?q=%22will+repeat+it+again+th

Do not use again with repeat unless the intended meaning is 'say something for the third time'.

Send or Take? (A Guide to Correct English Usage)

Actually, until I read Mr.Marius Hancu's post above, I used to belive that "repeat again" is a habitual error
and hence grammatically incorrect.

Anyway, thanks Mr. Marius Hancu once again, and also thanks Mr.Yoong Liat for your kind advice.

I checked, and you're right: Bryan Garner, Modern American Usage, considers repeat again a redundancy.
I will stay with those authors, including Dickens, who use them, esp in repeat again and again, for intensification/stress.

I totally agree with Marius. No matter what Western language you speak , it seems logical and intuitive to use repeat the way Marius has suggested.

AbilActually, until I read Mr.Marius Hancu's post above, I used to belive that "repeat again" is a habitual error
and hence grammatically incorrect.

believe (I think it is a typo.)

It is redundant. "Repeat" should have been replaced with " say".