In the Yellow Emperor's Yinyin Sutra? Three mirrors need ten thousand times a day and night? What does this mean?

The day is when people are awake, and the night is when people sleep. They think when they are awake and when they sleep. Moreover, when people are awake during the day, they need to concentrate on thinking and eliminate interference. In the sleep at night, people's thinking focuses on the essence and work freely.

The explanation of the three evils:

If people can bring thinking from consciousness to dreams and continue to speculate, there will be unexpected gains. Most importantly, after they wake up, they must reflect on the precious achievements in their dreams, otherwise they will be fleeting.

Meaning:

If people really think about something day and night, they must pay full attention to understanding it.

There is more than one source, in fact, all sources are empty, use it 10 thousand times!