What is the linguistic significance of the fasting verse?

If the verse regarding fasting refers to the Almighty's saying: "O you who have believed, decreed upon you is fasting as it was decreed upon those before you that you may become righteous," then "decreed" therein means obligation and compulsion. Linguistically, fasting is absolute abstention from something, and legislatively, it is abstaining from the desires of the stomach and the private parts from the rise of the true dawn until sunset.