凡事预则立,不预则废 “In all matters, preparation brings success. Without preparation, there is failure.” The line comes from the Doctrine of the Mean. The Handian dictionary explains yu as making plans or preparations in advance.
The dictionary’s example is from Mao Zedong’s On Protracted War. Mao quoted the line and added that without plans and preparations made beforehand, victory in war cannot be won.