Mencius uses digging a well as a metaphor: even after digging nine ren deep, quitting before striking spring water renders all labor futile. It stresses perseverance to the very end, warning against half-finished efforts in self-cultivation and undertakings.
Mencius states benevolence naturally defeats evil as water extinguishes fire. Many only make feeble moral efforts yet blame benevolence for failure, which sides with wickedness and leads to their own downfall eventually.