Assalamu’alaikum warahmatullahi wabarakatuh,
IN THE NAME OF ALLAH, THE MOST BENEFICENT, THE MOST MERCIFUL
The month of Muharram is the first month of the Arabic year, and it is one of the four sacred months of Allah. Allah says (interpretation of the meaning):
“Verily, the number of months with Allah is twelve months (in a year), so was it ordained by Allah on the Day when He created the heavens and the earth; of them four are Sacred (i.e. the 1st, the 7th, the 11th and the 12th months of the Islamic calendar). That is the right religion, so wrong not yourselves therein”
al-Bukhaari (3167) and Muslim (1679) narrated from Abu Bakrah (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: “The division of time has turned to its original form which was current the day Allah created the heavens and earth. The year consists of twelve months of which four are sacred: three consecutive months, Dhu’l-Qa’dah, Dhu’l-Hijjah and Muharram, and Rajab of Mudar which comes between Jumada and Sha’baan.”
It was proven from the Prophet (peace and blessings of Allah be upon him) that the best fasting after Ramadaan is fasting in the month of Muharram. It was narrated that Abu Hurayrah (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings of Allah be upon him) said: “The best fasting after Ramadaan is the month of Allah Muharram, and the best prayer after the obligatory prayer is prayer at night.” Narrated by Muslim, 1163.
With regard to the phrase “the month of Allah”, mentioning the month in conjunction with Allah is a sign of its great status. Al-Qaari said: it seems that what is meant is all of the month of Muharram.
But it was proven that the Prophet (peace and blessings of Allah be upon him) did not fast any month in full apart from Ramadaan, so this hadeeth is to be understood as meaning that it is it is encouraged to fast a lot in the month of Muharram, not to fast the whole month.
Allah knows best.