If Hezbollah joins they know Israel will destroy Lebanon, don't forget Israel has also nuclear weapons, but it has not acknowledged its nuclear forces.
The Mossad is also very capable to assassinate enemies around the world even deep inside Iran.
the problem israel is worried is not their forces but rather more is the missiles, which they have around 150K according to our intelligence this could destory israel because we are small country and iron dome is not 100%.
so the air force will have to act fast and bombed most of lebanon in couple of days or else we are screwed
