Israel has literally been bombing Lebanese territory for almost a year now, they just blew up random civilians in Lebanon, and now it is heavily implied that they are preparing an invasion if Lebanon.
At this point, there is no way that Hezbollah alone is prepared to resist Israeli aggression, surely the official Lebanese government and military is prepared as well?
The Lebanese military is extremely underfunded, hence the indispensability of Hezbollah. Before Hezbollah became a thing it was Palestinian guerilla fighters who took that role.
Their government is dealing with its own domestic shit. They haven't had a president since early last year.
Hezbollah has been part of the elected Lebanese government since the mid 00s I’m pretty sure. They just also maintain a militant wing who is more well known.