With regard to the Arab Legion’s participation in the attack on Jerusalem, Glubb wrote:
“I went back to my house, full of anxious forebodings. I know the extent of Jewish preparations. I knew that the Arabs had no plan and that there was no co-operation between them. We still had received no ammunition. The people expected us in two or three days to take Tel Aviv. How was I to act amid so much folly?
There seemed to be no alternative but to break in to Jerusalem from the north, clear the Sheikh Jarrah and establish contact with the Old City. Then a continuous line of defense could be built up across the city and the Jewish offensive halted.
As soon as I reached home, I went to my room and wrote out the signal myself. ‘I HAVE DECIDED TO INTERVENE IN FORCE IN JERUSALEM.’ DIVISONAL HEADQUARTERS WERE ORDERED TO ATTACK SHEIKH JARRAH AT DAWN ON THE 19TH AND BREAK THROUGH, SO AS TO ESTABLISH CONTACT WITH THE OLD CITY. THE 8TH INFANTRY COMPANY ON THE MOUNT OF OLIVES WAS TO MOVE FORWARD ACROSS THE KIDRON AND JOIN IN THE DEFENSE OF THE OLD CITY. THE DIE WAS CAST.”
Source: Memoirs of Lieutenant General John Glubb of the British Army and Commander of Arab Legion