In the name of Allaah, the most Merciful, the Bestower of Mercy
Fasting is an obligation, which Allaah prescribed on every Muslim  that is sane and has reached the age of puberty. Allaah says:
"O you who believe! Fasting is prescribed for you as it was prescribed for those before you, in order that you may attain Taqwaa." [Surah Al-Baqarah: 183]
The specified time when it becomes obligatory is the month of Ramadaan of every year. Allaah says:
“The month of Ramadaan in which was revealed the Qur'aan, a guidance for mankind and a clear proof 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 Ramadaan), then he must observe the Fast (that month)." [Surah Al-Baqarah: 185]
Fasting in the month of Ramadaan is one of the pillars of Islaam. The Prophet (صلى الله علیه وسلم) said:
“Islam is built on five things: (1) Testifying that there is no deity worthy of worship except Allaah, and that Muhammad is the Messenger of Allaah, (2) Establishing the prayer, (3) Giving the Zakaat, (4) Performing Hajj, and (5) Fasting in Ramadaan.”[/i] [Reported by Al-Bukhaaree and Muslim]
So whoever breaks his fast intentionally in the month of Ramadaan without a valid Islamic excuse, he has destroyed one of the pillars of Islaam and stepped into the realm of great danger.
The person who is fasting abstains from food, drink and sexual intercourse with his wife – intending  worship by that – from dawn until sunset. So when the sun sets, all of these things become permissible for him. Allaah says:
“It is made lawful for you to have sexual relations with your wives on the night of Fasting. They are a covering for you and you are a covering for them.” [Surah Al-Baqarah: 187]
And Allaah says in the same ayah:
“And eat and drink until the white thread (light) of dawn appears to you distinct from the black thread (darkness of night). Then complete your Fast until the nightfall.” [Surah Al-Baqarah: 187]
 The word “Muslim” includes both male and female.
 The place for the intention is the heart, so it should not be pronounced (on the tongue).