"Seven don't go out" means to do seven things for the family before going out: firewood, rice, oil, salt, sauce, vinegar and tea. "Eight no return" refers to checking whether you have done eight things well before going home: filial piety, loyalty, faithfulness, courtesy, righteousness, honesty and shame. As the old saying goes, "If you don't leave for seven days, you won't return for eight days". Everyone thinks what you said is: don't go out on the seventh day and don't go home on the eighth day. Some people even counted seventeen, eighteen, twenty-seven and twenty-eight.
Seven came out to talk about housekeeping. Doing housework makes family members energetic and healthy and happy. Not returning is the principle of being a man and the foundation of a family. China's 5,000-year-old traditional culture is profound, and every old saying handed down has its profound connotation. However, we have been deceived by the ambiguous solution of "reading literature to create meaning" for many years.