Its mentioned in the Quran Allah Almighty says, “O you who believe! Observing As-Saum (the fasting) is prescribed for you as it was prescribed for those before you, that you may become Al-Muttaqun. [Surah Al Baqarah 183 – Translation: Muhsin Khan,The Noble Quran] – This is regarding Compulsory [Fard] fasting (in Ramadan). But its valid in case of voluntary [sunnah] fasts as it will increase God-consciousness [Taqwa].
