Here the author refers to himself by his "heart" to emphasize his feelings. See how you translated this in [Ecclesiastes 1:17](../01/17.md). Alternate translation: "I applied myself" (See: [[rc://en/ta/man/translate/figs-synecdoche]])
This can be stated in active form. Alternate translation: "the work that people do on the earth" (See: [[rc://en/ta/man/translate/figs-activepassive]])