It happened. Hezbollah fought and chased the Israeli out of South Lebanon and they provided help to the Bosnians. Even in this conflict Hezbollah could have completely stayed neutral but they chose to start targeting Israelis assets over the border, for which they have almost lost everything now. Let’s be historically accurate even we disagree with the twelvers.
I don’t doubt that they will fight invading zionists who plan to annex their territory (south Lebanon) into greater israel. What I doubt is it going any further to materially help the Palestinians.
The zionists have made it clear for a decade now they plan to attack iran and it’s allies. They do not want Muslims to have any strong military or independence so it was inevitable. It is in their interest of self preservation to resist this.
They will come for the Egyptian military too eventually. They are the ones who funded and helped Ethiopia build its dam to weaken Egypt. They want the Muslim world to be weak and further divided so that no one rises in the future that could fight them.