The word “Saum” appears 10 times in 7 verses in the Quran.
The Muslim fast of the month of Ramadan is a continuation of the long history of fasting in the Abrahamic faiths.
”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 (the pious).” (Al-Baqara [The Cow], Chapter #2, Verse #183)
[Observing Saum (fasts)] for a fixed number of days, but if any of you is ill or on a journey, the same number (should be made up) from other days. And as for those who can fast with difficulty, (e.g. an old man), they have (a choice either to fast or) to feed a Miskin (poor person) (for every day). But whoever does good of his own accord, it is better for him. And that you fast is better for you if only you know.** (Al-Baqara [The Cow], Chapter #2, Verse #184)
The month of Ramadan in which was revealed the Qur’an, a guidance for mankind and clear proofs for the guidance and the criterion (between right and wrong). So whoever of you sights (the crescent on the first night of) the month (of Ramadan i.e. is present at his home), he must observe Saum (fasts) that month, and whoever is ill or on a journey, the same number [of days which one did not observe Saum (fasts) must be made up] from other days. Allah intends for you ease, and He does not want to make things difficult for you. (He wants that you) must complete the same number (of days), and that you must magnify Allah [i.e. to say Takbir (Allahu Akbar; Allah is the Greatest] for having guided you so that you may be grateful to Him.** (Al-Baqara [The Cow], Chapter #2, Verse #185)
“Indeed We have revealed it (Qur’an) in the night of Power. And what will explain to you what the night of Power is? The night of Power is better than a thousand months. Therein descends the Angels and the Spirit (Jibreel) by Allah’s permission, on every errand: (they say) “Peace” (continuously) till the rise of Morning!” (Q 97:1-5)