Seven Pillars of Wisdom by T.E. Lawrence

However, the Arab Movement lived on Allenby's good pleasure, so it was needful to undertake some operation, less than a general revolt, in the enemy rear: an operation which could be achieved by a raiding party without involving the settled peoples; and yet one which would please him by being of material help to the British pursuit of the enemy.

These conditions and qualifications pointed, upon consideration, to an attempted cutting of one of the great bridges in the Yarmuk Valley.