This refers to things that are done on earth. See how you translated this in [Ecclesiastes 1:3](../01/03.md). Alternate translation: "on the earth" (See: [[rc://en/ta/man/jit/figs-idiom]])
This means that their oppressors were powerful. Here their "hand" represents what thet possess. Alternate translation: "Their oppressors were powerful" (See: [[rc://en/ta/man/jit/figs-metonymy]])