觀無量壽佛經疏 1.7

1.7

Next, to distinguish the function of the sūtra: function means power and function. Producing goodness and eliminating evil are the power and function of the sūtra. Because it eliminates evil, it is called power; because it produces goodness, it is called function. Because it eliminates evil, it is called efficacy; because it produces goodness, it is called virtue. These are each partial descriptions; a complete explanation must encompass both. Suffering is the fruit of evil; greed, anger, and delusion are the causes of evil. If evil causes are not eliminated, the fruits cannot cease. Therefore, that this sūtra can cause the sins of the five heinous deeds to be extinguished and bring about rebirth in the pure land is precisely the great power and function of this sūtra.