Hamas was founded in December 1987. Israeli officials say the killing in Gaza began on 7 October 2023, as if there were no history before it. There was. These are 25 times Israeli forces massacred Palestinians before Hamas existed, from the day the state was declared to 1982.
The list starts on 14 May 1948, because before then Israel did not exist. Zionist militias had already carried out massacres by that date, most infamously at Deir Yassin on 9 April 1948, where Irgun and Lehi fighters killed more than 100 villagers. Weeks later, those groups were folded into Israel's army.
It is a fraction of the documented record. Historians count dozens of massacres in 1947 to 1949 alone; Benny Morris counts 24 in 1948, and the Palestinian historian Saleh Abd al-Jawad's study Zionist Massacres (2007) lists far more.
Every figure below is the lowest the sources support. Where one exists, each links to its dated entry on isitolderthanisrael.com, with the record behind it.
1. Abu Shusha, 14 May 1948

The Givati Brigade took Abu Shusha, near Ramla, on the day Israel was declared. About 60 villagers were killed. See the entry.
39 years before Hamas existed.
2. al-Bassa, 14 May 1948

Haganah troops took al-Bassa, near the Lebanese border, the same day. Witnesses said soldiers herded villagers into the church and shot at least five people before driving the rest out.
39 years before Hamas existed.