To "swear" is to say that you will do something, or that something is true, and to be held accountable by a higher authority. Alternate translation: "do not make an oath" or "do not make a vow"
The words "heaven" and "earth" refer to the spiritual or human authorities that are in heaven and earth. (See: [[rc://en/ta/man/translate/figs-metonymy]])
Being condemned is spoken of as if one had fallen, crushed by the weight of something heavy. Alternate translation: "so God will not punish you" (See: [[rc://en/ta/man/translate/figs-metaphor]])