While Israel tries to defeat Hamas, they also have to worry about a much more dangerous paramilitary group on their northern border: Hezbollah.The express purpose of Hezbollah, which formed 40 years ago, is also to eradicate Israel.It would be a nightmare for Israel if Hezbollah swings in and backs Hamas up.So where did Hezbollah form, why do they hate Israel, and what hand did Israel have in their creation?Subscribe to If You're Listening on the ABC Listen app.Catch up on our series about the Israel-Gaza conflict on YouTube: https://www.youtube.com/watch?v=aQ4x0gAzJx4