注維摩詰經 4.190

4.190

生曰：魔天以不信正為本，故令信佛也。夫理本無定，苟能樂之，則為樂矣。既樂而恒，又益樂也。

[Dao]sheng says: The Māra heaven takes lack of faith in the correct as its foundation; hence he causes them to have faith in the Buddha. Principle is fundamentally not fixed; if one can take joy in it, then it becomes joy. When joy is constant, it becomes even more joyful.