There are 5 Tenets (pillars or principles) of Islam, (i) Shahadah (Iman - faith), (ii) Salah (Distinctive Submission - a form of Islamic Prayer ), (iii) Zakah (Islamic Charity), (iv) Sawm (Islamic Fasting), (v) Hajj (Pilgrimage to Makkah).
It is in Hadith - Narrated by Ibn Umar (RU) - Allah's Apostle (SAWS) said - Islam is based on (the following) five (principles) - (i) 'there is no (real) god except Allah (SWT) and Mohammad (SAWS) is Allah's Apostle, (ii) to offer Salah ( prayers) dutifully and perfectly, (iii) to pay Zakat (Islamic charity), (iv) to perform Hajj (Pilgrimage to Makka), and (v) to observe fast during the month of Ramadhan. (Bukhari Book 2 Hadith 7 )
Islamic fasting (Saum) is an act of Ibadah and the fourth tenet of Islam. We are required to fast from dawn to dust every day during the month of Ramadhan, every lunar year.
Fasting means, abstaining from eating, drinking, smoking and sexual relations (between spouses) during the hours of fasting. Travelers, sick and certain other categories can defer fasting in Ramadhan but they are required to complete the left over fasts in the following months.
The objective of fasting is not that one merely abstains from the material and physical things which break one’s fast, but rather, one must also refrain from those intangible things which diminish the reward of one’s fast, such as backbiting, deception, unnecessary gossip, etc.
There are many benefits of fasting to human body and soul. Following Quranic verses and Ahadith emphasize the importance of Islamic fasting.
It is in Quran - "O you who believe; fasting is prescribed for you as it was prescribed for those before you that you are expected to be truly obedient". (Al-Baqara - 183)
It is in Hadith - “Whoever does not refrain from false speech and deeds, Allah (SWT) has no need for him to leave his food and drink.” (Bukhari)
It is in Quran - "Verily! We have sent it (this Quran) down in the night of Al-Qadr. And what will make you know what the night of Al-Qadr is? The night of Al-Qadr is better than a thousand months. Therein descend the angels and the Rûh (Gabriel) by Allâh's Permission with all Decrees, Peace! (All that night, there is Peace and Goodness from Allâh to His believing slaves) until the appearance of dawn. (Al-Qadar - 1-5).It is in Hadith that Lailatul Qadar occurs during the last ten days of Ramadan. This night has great significance, therefore, it should be spent in Ibadah.
Tarawih (20 rakah) is offered during the month of Ramadhan after Isha. Salatut Tarawih is sunnah. It is generally offered in congregation. Those who cannot join a congregation, can offer Tarawih at home.
A pre-dawn meal known as Suhur is usually taken in Ramadan.
At the end of Ramadan Muslims celebrate Eid-ul-Fitr on 1st Shawwal. All Muslims are required to offer special prayers on this day in congregation to thank Allah (SWT) for His Mercy.
Similarly, Muslims celebrate Eid-ul-Azha on 10th of Dhu'l-Hijja every year. They offer special prayers in congregation on this day to thank Allah (SWT) for his beneficence. They also sacrifice a domestic Halal animal, such as a sheep, goat, cow, or camel, by slaughter.