Briefing on Hezbollah
On 4th December, 2018 the IDF launched Operation `Northern Shield` with the intention of exposing and thwarting "cross border attack tunnels dug by the Hezbollah terror organisation"
In light of today's events, here is some useful material for providing context.
Additionally, see research by BICOM on Hezbollah
http://www.bicom.org.uk/analysis/hezbollahs-hold-on-lebanon-implications-for-a-third-lebanon-war/
http://www.bicom.org.uk/analysis/bicom-strategic-assessment-second-lebanon-war-10-years/