How did arab nationalism contribute to the civil war in 1948

Arab nationalism contribute to the civil war in 1948 because of the impact of British foreign policy and consequently United Nations policy regarding the Middle East. After the First World War, both sides, Zionists and Arab nationalists believed Palestine had been promised to them by the British. Therefore there were already inconsistencies in British policy as neither side knew where they stood. After the Second World War, Britain held the mandate for Palestine.