Narrated Abu Huraira (Radi-Allahu 'anhu):
Allah's Apostle (Sallallahu 'Alaihi Wa Sallam) said, "Fasting is a shield(or a screen or a shelter). So, the person observing fasting should avoidsexual relation with his wife and should not behave foolishly and
impudently, and if somebody fights with him or abuses him, he should tellhim twice, 'I am fasting." The Prophet (Sallallahu 'Alaihi Wa Sallam)added, "By Him in Whose Hands my soul is, the smell coming out from the
mouth of a fasting person is better in the sight of Allah than the smell ofmusk. (Allah says about the fasting person), 'He has left his food, drinkand desires for My sake. The fast is for Me. So I will reward (the fasting
person) for it and the reward of good deeds is multiplied ten times."
Bukhari Vol. 3 : No. 118