JUSTIN BIEBER is being sued by an ex-bodyguard, for BEATING ON HIM.     And to make this lawsuit even more ridiculous, this guy is one of those former Israeli military guys who are so popular in the bodyguarding world because they're, like, the biggest badasses on the planet.

The dude's name is Moshe Benabou, and he worked for Justin from March of 2011 to October of 2012.  And he claims Justin was ABUSIVE.  During one incident, he claims Justin berated him and punched him in the chest multiple times.  He's seeking unspecified damages for assault and battery, plus $420,000 in unpaid overtime.

A source close to Justin calls the guy, "a disgruntled employee looking for money", and says the idea that Justin hit him is ABSURD.

Moshe was actually fired, apparently for being a pretty habitual liar.  He even lied to get the job in the first place by falsely claiming he had previously worked with JUSTIN TIMBERLAKE. 

(Moshe is the guy who got into it with a photographer at LAX early last year, and clocked him in the face.  Here's that video.)