Green marking with a dagger stabbing a Magen David.  Historical status as a flag is unknown, possibly dubious, but as a historical emblem or insignia, see image [1] linked from  [2], File:The army of liberation works wonders al mussawar 19480403.jpg, and File:Qawuqjis armored vehicle.jpg
Own work, http://www.ynet.co.il/PicServer2/02022009/2084251/12-Zklarts_043_wh.jpg
original version by Vallecyofdawn, modified version by Zscout370