《左传·襄公·襄公二十三年》
《夏书》说： 想着这个，一心在于这个 ，这就是顺于事理，合于恕道啊。 
《夏书》曰： 念兹在兹。 顺事恕施也。 
Xia Shu said: Thinking about it, devote oneself to it and to no other, that is going with the nature and being appropriate to the kind.