He says (nigga) not (friend) there's a difference if you didn't know here's the difference.
friend - The term friend is now probably the most offensive word in English. Its degree of offensiveness has increased markedly in recent years, although it has been used in a derogatory manner since at least the Revolutionary War. The senses labeled Extremely Disparaging and Offensive represent meanings that are deeply insulting and are used when the speaker deliberately wishes to cause great offense. It is so profoundly offensive that a euphemism has developed for those occasions when the word itself must be discussed, as in court or in a newspaper editorial: “the n-word.”
Despite this, the sense referring to a “black person” is sometimes used among African Americans in a neutral or familiar way. The sense referring to other victims of prejudice, especially when used descriptively, as to denounce that prejudice, is not normally considered disparaging—as in “The Irish are the friends of Europe” from Roddy Doyle's The Commitments —but the other uses are considered contemptuous and hostile.
Nigga - Nigga is used mainly among African Americans, but also among other minorities and ethnicities, in a neutral or familiar way and as a friendly term of address. It is also common in rap music. However, nigga is taken to be extremely offensive when used by outsiders. Many people consider this word to be equally as offensive as friend. The words friend and nigga are pronounced alike in certain dialects, and so it has been claimed that they are one and the same word.
Source -
http://dictionary.reference.com/