Quite a few were Christian Arabs
As was much of the leadership of the resistance of the folks who lost their land
ALL ARABS CELEBRATE PRO-PHET'S BIRTHDAY; Christians Join Moslems in Fete Unprecedented in Palestine--Hitler and Duce Cheered, The New York Times, May 23, 1937.
More on Islamized “christian” Arabs of Palestine:
Issa Nakhleh (1915-2003): A supposed “Christian” - After a long bloody Neo-Nazi career, he published a glorification of Islam, Muhammad
https://freerepublic.com/focus/f-religion/4104974/posts