Start: Surveying the wreckage of a neighbor’s bungalow hit by a Palestinian rocket, retired Israeli official Avner Cohen traces the missile’s trajectory back to an “enormous, stupid mistake” made 30 years ago. “Hamas, to my great regret, is Israel’s creation,” says Mr. Cohen, a Tunisian-born Jew who worked in Gaza for more than two decades. Responsible for religious affairs in the region until 1994, Mr. Cohen watched the Islamist movement take shape, muscle aside secular Palestinian rivals and then morph into what is today Hamas, a militant group that is sworn to Israel’s destruction.

Other sources:

https://theintercept.com/2018/02/19/hamas-israel-palestine-conflict/

https://www.washingtonpost.com/news/worldviews/wp/2014/07/30/how-israel-helped-create-hamas/

'Israel’s military-led administration in Gaza looked favorably on the paraplegic cleric (Ahmed Yassin, founder of Hamas), who set up a wide network of schools, clinics, a library and kindergartens. Sheikh Yassin formed the Islamist group Mujama al-Islamiya, which was officially recognized by Israel as a charity and then, in 1979, as an association. Israel also endorsed the establishment of the Islamic University of Gaza, which it now regards as a hotbed of militancy. The university was one of the first targets hit by Israeli warplanes in the [2008-9 Operation Cast Lead].

A strange, self-sustaining relationship remains. Israel’s hawkish government — dwells on the security threat that Hamas’s crude rockets pose. Hamas depends, Miller writes, on “an ideology and strategy steeped in confrontation and resistance.”

He concludes, they are "two parties who can’t seem to live with one another — or apparently without one another either.’