"اِنَّ عِدَّةَ الشُّهُوۡرِ عِنۡدَ اللّٰهِ اثۡنَا عَشَرَ شَهۡرًا فِىۡ كِتٰبِ اللّٰهِ يَوۡمَ خَلَقَ السَّمٰوٰتِ وَالۡاَرۡضَ مِنۡهَاۤ اَرۡبَعَةٌ حُرُمٌ ؕ ذٰ لِكَ الدِّيۡنُ الۡقَيِّمُ ۙ فَلَا تَظۡلِمُوۡا فِيۡهِنَّ اَنۡفُسَكُمۡ ؕ وَقَاتِلُوا الۡمُشۡرِكِيۡنَ كَآفَّةً كَمَا يُقَاتِلُوۡنَكُمۡ كَآفَّةً ؕ وَاعۡلَمُوۡۤا اَنَّ اللّٰهَ مَعَ الۡمُتَّقِيۡنَ "
The Islamic calendar, also known as the Hijri or Arabic calendar, is a lunar calendar consisting of 12 lunar months in a year of 354 or 355 days. Muharram is the first month of the Islamic calendar. There is a very vast Islamic history associated with this month. It includes the unfortunate battle of Karbala in which the beloved grandson of Prophet Muhammad (SAW), Husain ibn Ali had sacrificed his life. Generally, people today remember this month only due to this incident, but there are lots beyond this. The sacredness and virtue of Muharram have already been described in the Quran much before this unfortunate incident.
Muharram is one of the holiest months in Islam which can be understood by the verse of the Quran written above. The translation of the above ayat is- “Surely the reckoning of months, in the sight of Allah, in the sight of Allah, is twelve months, laid down in Allah's decree on the day when He created the heavens and the earth; and out of these months, four are sacred. That is the true ordainment. Do not, therefore, wrong yourselves, concerning these months.
And fight all together against those who associate other with Allah in His divinity in the manner which they fight against you all together against those who associate others with Allah in His divinity in the manner which they fight against you all together, and know well that Allah is with the God-fearing.” (Surah 9 - At-Tawba - Ayah 36). It can be concluded from the above ayah that heaven and earth have been created by Allah this month and Muharram is one of the four sacred months and First month of The Islamic Calendar.
At this point also, there should be no misconceptions about fasting. Hazrat Abbas (RA) narrates, “Prophet Muhammad (SAW) came to Madina and saw the Jews fasting on the day of Ashoora, as because this is a righteous day, it is the day when Allah saved the Children of Israel from their enemies, so Moosa fasted on this day.’ He said, ‘We have more right to Moosa than jews,’ so He fasted on that day and commanded (the Muslims) to fast on that day.” (Bukhari)
Regarding fasting on Ashura, Prophet Muhammad (SAW) said, “This fast is a compensation for the (minor) sins of the past year.” (Muslim)
The above hadith shows the importance of fasting on Ashura. And also, how fasting on this day has significance even before our prophet.
Abu Hurairah (may Allah be pleased with him) said: “The Messenger of Allah (peace be upon him) said: ‘The best of fasting after Ramadan is fasting Allah’s month of Muharram.” (Muslim)
Ashura is the 10th day of the holy month of Muharram, the first month of the Islamic Calendar. And the fasting on this day is not mandatory like in Ramadhan, it is Nafil.
The day starts with Sehri followed by fajr salah. As the whole day is for fasting, we should make Dua and Zikr throughout the day. The evening starts with Aftaar followed by Maghrib salah.