Albert Barnes on Matthew 24:11

And many false prophets. Many men, pretending to be prophets, or foretellers of future events. This refers not to the false Messiahs of which he had spoken, Mt 24:6 but to prophets who should appear during the siege of the city. Of them Josephus says, "The tyrannical zealots who ruled the city suborned many false prophets to declare that aid would be given to the people from heaven. This was done to prevent them from attempting to desert, and to inspire confidence in God." See Jewish Wars, book vi., Chap. 5, & 2, 3.

(l) "And many false" 2Pet 2:1, 1Jn 4:3 (m) "deceive many" 1Timm 4:1