According to Khaled al-Azm, who served as Prime Minister of Syria in 1948–1949 and multiple times thereafter, the Arabs in Palestine left because Arab leaders encouraged them to flee, promising a swift military victory over the nascent State of Israel.
In his memoirs, al-Azm wrote the following revealing statement:
"Since 1948, it is we who demanded the return of the refugees… While it is we who made them leave… we brought disaster upon… the Arab refugees, by calling on them to leave their homes."
— Khaled al-Azm, Memoirs, Part 1, p. 386–387
This quote has been cited in discussions to highlight that Arab leadership bore responsibility—in part—for the mass departure of Arabs from British Mandate Palestine during the 1948 Arab-Israeli War. Many Arabs fled expecting the invading Arab armies (from Syria, Egypt, Jordan, Iraq, and Lebanon) would defeat the Jews quickly, after which they could return.