Q:

When and where did "idren" enter the English language?

The first time that I heard the word idren was in the song "Bad Boys", which is the theme song for the television show "COPS". When and where did this word enter the English language?
The song lyrics are in English, but idren is an unusual word.
Bad Boys (theme from Cops)

Nobody naw give you no break
  Police naw give you no break
  Soldier naw give you no break
  Not even you 'idren naw give you no break
  Hey

A:

Idren is a plural noun originated from Rastafari  English which means:

One's peers, or spiritual brothers and sisters.

It derives from a blend of I and bredren, another Rastafarian term which means  a close friend, a family member, a comrade.
Rastafarian English is a dialect primarily spoken by Jamaican Rastafarians. The Rastafarian language is different from  Jamaican Patois because it is a play on English words, rather than being an entirely separate dialect.  The Rastafarian movement, which began in the 1930s in Jamaica, is based on positive beliefs like unity, peace, and one love. So Rastafarian language is a reflection of these positive beliefs.
The following interesting paper by Benjamin Slade:
Overstanding Idren:
Special Features of Rastafari English Morphology explains that the formation of I-words is typical of Rastafarian  dialect:

I-words, I would argue, are even further removed  om word-play and punning than are over- standings. Thus I disagree with Nettleford’s assessment:
”The play on words—a Jamaican facility that extends  om theatrical punning to every- day speech—is artlessly embraced by the Rastafarian in the repertoire of “I” (ai) words which Mrs Pollard indicates will, on closer examination, disclose that “ai” is not merely used as a pronominal form to replace the Jamaican Creole “mi” but is also used as prefix to some nouns a replacement for the initial sound in any number of words of varying function in a sentence.(Nettleford, in introduction to Pollard 2000: xi–xii)”

and I-words formations are often applied to term with “spiritual” and “social “ connotations such as:

a. Iration < creation
b. Iman   < human (but meaning similar to pronominal “I” (see above))
c. Ital “spiritually clean food, ∼ kosher, halal” < vital
d. Idren “male or female co-Rasta(s)” < bredren(brethren)/sistren
e. Iwa < hour, but generally meaning “time”.

