Allâh's Messenger (ﷺ) said, "Saum (fasting) is a shield (or a screen or a shelter from the Hell-fire [1]). So, the person observing Șaum (fast) should avoid sexual relation with his wife and should not behave foolishly and impudently, and if somebody fights with him or abuses him, he should say to him twice, 'I am observing Ṣaum (fast). ' " The Prophet (ﷺ) added, "By Him in Whose Hands my soul is, the smell coming out from the mouth of a person observing Șaum (fast) is better with Allâh than the smell of musk. (Allâh says about the fasting person), 'He has left his food, drink and desires for My sake. The Saum (fast) is for Me. [2] So I will reward (the fasting person) for it and the reward of good deeds is multiplied ten times. ' " [3:118-O.B]

The Prophet (ﷺ) said, "There is a gate in Paradise called Ar-Raiyân, and those who observe Şaum (fasts) will enter through it on the Day of Resurrection and none except them will enter through it. It will be said, 'Where are those who used to observe Şaum (fasts)? ' They will get up, and none except them will enter through it. After their entry the gate will be closed and nobody will enter through it." [3:120-O.B]

Allâh's Messenger (ﷺ) said, "Whoever gives two kinds (of things or property) in charity for Allâh's Cause, will be called from the gates of Paradise and will be addressed, 'O slaves of Allâh ! Here is prosperity. 'So, whoever was amongst the people who used to offer their (prayers) will be called from the gate of the Salât (prayer); and whoever was amongst the people who used to participate in Jihâd, will be called from the gate of Jihad; and whoever was amongst those who used to observe Șaum (fasts), will be called from the gate of Ar-Raiyân; whoever was amongst those who used to give-Şadaqa (charity), will be called from the gate of As-Sadaqa (charity)." Bakr said, "Let my parents be sacrificed for you, O Allâh's Messenger (ﷺ)! No distress or need will befall him who will be called from those gates. Will there be any one who will be called from all these gates?" The Prophet (ﷺ) replied, Yes, and I hope you will be one of them." " [3:121-O.B]

Allah's Messenger (ﷺ) said: "When (the month of Ramaḍân begins, the gates of Paradise are opened." [3:122-O.B]

Allah's Messenger (ﷺ) said, "When the month of Ramaḍân starts, the gates of the heaven are opened and the gates of Hell are closed and the devils are chained. [3:123-O.B]

I heard Allâh's Messenger (ﷺ) saying, you see the crescent (of the month of Ramaḍân), start observing Ṣaum (fast), and when you see the crescent (of the month of Shawwâl), stop observing Saum (fast); and if the sky is overcast (and you can't see it) then regard the crescent (month) of Ramaḍân (as of 30 days)." [3:124-O.B]

The Prophet (ﷺ) said, "Whoever does not give up lying speech (false statements) and acting on those lies and evil actions etc., Allâh is not in need of his leaving his food and drink [i.e. Allah will not accept his Ṣaum (fasting)]." [See Fath Al-Bâri, Vol. 5, Page 18] [3:127-O.B]