Rich Homie Quan: Cut Him a Break on Biggie Flub ... Says Faith Evans

Biggie's ex wife, Faith Evans, is defending Rich Homie Quan after what some are calling a career-murdering flub during the VH1 "Hip Hop Honors," but she also says he needs to bone up on hip-hop history.

RHQ hopped onstage for Lil Kim's Junior M.A.F.I.A. classic, "Get Money" ... but forgot most of the Biggie lyrics he was supposed to spit. It started when RHQ rapped "Play Nintendo with Cease and Alamo" ... instead of "with Cease and Nino" -- and it all went downhill from there.

Faith says if RHQ had a clue about Junior M.A.F.I.A. members Lil' Cease and Nino Brown ... he wouldn't have screwed up that lyric.

Still, Biggie's ex-wife thinks people should let Quan off the hook because everyone makes mistakes.

Hip-hop fans, especially in NYC, haven't been that forgiving, but hey ... it wasn't "The Star-Spangled Banner" at the Super Bowl.