“All is vanity”: this includes the inevitable decline of human life that comes with aging. Since this is true, the Teacher urges all to remember the Creator.
This final segment of the book puts the focus on the Creator God. Here is an extended allegory, portraying the gradual loss of bodily strength in terms of a house that is falling apart (the “guards” = arms; “strong men” = legs; “women who grind” = teeth; “those who look through the windows” = eyes; “doors on the street” = ears).
Finally, the theme of “vanity” is sounded a last time (12:8), and 12:13 stands as a short summary of the instruction of the entire book: “Fear God, and keep his commandments.”