Laojun Neiguan Jing 太上老君内观经 Taishang Laojun Neiguan Jing

Laojun Neiguan Jing, also known as Taishang Laojun Neiguan Jing, was probably composed around the Sui-Tang period. The content of the scripture focuses on the method of inner observation and calming the mind, stating that the human heart is inherently pure and tranquil, but it falls into the sea of suffering due to being contaminated by the six emotions. "If the heart is pure and tranquil, all misfortunes will not arise." Cultivating the Dao is essentially cultivating the heart, and its key lies in "observing one's own body inwardly to purify the heart."

The method of inner observation begins with reflecting that among all things, humans are the most noble, so one should not recklessly be contaminated by various mundane dusts. Then, one should eliminate the six consciousnesses and six desires, empty the mind of selfishness, stabilize and settle the mind, calm and rectify the mind, and purify the heart. When the heart is calm and the spirit is stable, it reaches a state where "disorderly thoughts do not arise, evil delusions do not invade; both the body and external things are stabilized; closing the eyes and pondering, the interior and exterior are empty and silent, and the divine Dao is subtle and profound."

It also says that cultivating the heart must be combined with refining the body, so that essence and qi do not disperse, and purity remains undivided, thus achieving "the unity of body and spirit with the Dao, and ascending to Kunlun."