It is the best of months for general voluntary fasts, after Ramadan. It is especially recommended to fast the 10th of Muharram (known as the Day of `Ashura’), with a day before it or after it. [Ibn Abidin, Radd al-Muhtar, quoting Kasani’s al-Bada’i`]
Extracts from Ibn Rajab’s Lata’if al-Ma`arif, regarding the month of Muharram:
The Virtues of Fasting in the Month of Muharram and Its First Ten Days:
Muslim reported from Abu Hurayra (Allah be pleased with him), that the Prophet (Allah bless him and give him peace) said , “The best of fasts after the month of Ramadan are in the Month of Allah, which you call Muharram. And the best of prayer after the obligatory prayer is the night prayer.” [Muslim, 1163]
This refers to general voluntary fasts according to Imam Ibn Rajab : These are best in the month of Muharram, just as the best general voluntary prayer is night prayer.
The virtue and honor of this month can be attested to by the fact that the Prophet (Allah bless him and give him peace) called it, ‘the Month of Allah.’ (Shahr Allah) Such ascription is only made by Allah to the most special of His creation, such as the ascription of the Prophets Muhammad, Ibrahim, Ishaq, Ya`qub, and others to his slavehood (Allah’s peace and blessings be on them all), and His ascription of the House (Ka`ba) and the camel to himself.
Given that Allah ascribed fasting, between all spiritual works, to Himself [saying, “It is Mine,”] it was suitable that this month, which is also ascribed to Allah, be selected for this particular form of worship.
Fasting is a secret between the servant and his Lord. This is why Allah Mighty and Exalted says, [in the divine hadith (hadith qudsi)], “ Every action of the son of Adam is his, except for fasting. It is Mine, and it is I who reward it.” [Bukhari and Muslim, from Abu Hurayra]
The Prophet (Allah bless him and give him peace) also said, “The fasting person has two joys: one when he breaks his fast, and the other when he meets his Lord.”[Muslim]
As for voluntary night prayer (qiyam al-layl), it is superior to voluntary prayer during the day because it is closer to secrecy, and nearer to sincerity (ikhlas).
Allah Most High said, “Lo! the vigil of the night is (a time) when impression is more keen and speech more certain.” [Qur’an, 73.9]
This is because the time of the night vigil (tahajjud) is the best of times for voluntary prayer, and the closest a servant gets to his Lord. It is a time when the doors of the skies are opened, supplications answered, and needs fulfilled.
Allah Most High has praised those who wake up at night in His remembrance, supplication, seeking forgiveness, and intimate entreating (munajat), saying, “Who forsake their beds to cry unto their Lord in fear and hope, and spend of that We have bestowed on them. No soul knows what is kept hid for them of joy, as a reward for what they used to do.”[Qur’an, 32.16-17]
And, “Or he who pays adoration in the watches of the night, prostrate and standing, bewaring of the Hereafter and hoping for the mercy of his Lord? Say: Are those who know equal with those who know not? But only those of understanding will pay heed.” [Qur’an, 39.9]
And He said to His Prophet (Allah bless him & give him peace), “And some part of the night awake for it, as voluntary worship for you. It may be that thy Lord will raise thee to a praised estate.” [Qur’an, 17.79]
It has been said that those who worship at night will enter Paradise without reckoning, and that standing in night prayer shortens the length of one’s Standing on the Day of Judgment.
This is why the Prophet (Allah bless him & give him peace) said, “Stick to night prayer, for it was the way of the righteous before you. Night prayer is a means of closeness to Allah Most High, of expiating for bad deeds, avoiding sins, and keeping away illness from one’s body.” [Tirmidhi (3543], Bayhaqi, and others; it is a sound (hasan) hadith]
Similarly, it has been related that fasting is a means for good health. The Prophet (Allah bless him & give him peace) is reported to have said, “Fast, and you shall have good health.” [Ahmad, from Abu Hurayra]
Lovers have no time more joyous than when they are alone in entreating their Beloved. This is the healing for their hearts, and the great thing that they could long for.
This is why Abu Sulayman al-Darani would say, “The people of the night find more joy than the people of distraction (lahw) in their distractions. Were it not for the night, I would not like to remain living.”
The Day of `Ashura’: The Tenth of Muharram
It is mentioned in Bukhari and Muslim from Ibn Abbas (Allah be pleased with him and his father) that he was asked about fasting the Day of `Ashura’ [10th of Muharram]. He said, “I did not see the Messenger of Allah (blessings and peace be upon him) fast a day while more avid to seek its virtue than this day,” meaning the Day of `Ashura’.” [Bukhari (2006), and Muslim (1132)].
The Day of `Ashura’ has great virtue, and tremendous sanctity (hurma). The virtue of fasting it was known among the Prophets (peace be upon them all). Both Prophet Nuh and Prophet Musa (peace be upon them both) fasted it.
The Prophet (Allah bless him & give him peace) used to fast this day even in Mecca, though he had not yet ordered others to do so, as mentioned in both Bukhari and Muslim. [Bukhari (2002), Muslim (1125)]
When he migrated to Medina, and found the People of the Book fasting this day and venerating it, he ordered the Muslims to fast it, and encouraged it so much that even the children would fast it.
It has been reported in both Bukhari and Muslim from Ibn Abbas (Allah be pleased with him), that, “When the Messenger of Allah (blessings and peace be upon him) reached Medina, he found the Jews fasting the Day of `Ashura’, so he asked them, ‘What is this day you are fasting?’ They said, ‘This is a tremendous day. Allah saved Musa and his people on this day and drowned Pharaoh and his people. Musa fasted it out of thanks, so we fast it too.’ The Messenger of Allah (blessings and peace be upon him) said, ‘And we are more deserving of Musa than you are.’ So he fasted this day, and ordered that it be fasted.” [Bukhari (2004) and Muslim (1130)]
At the end of his life, the Messenger of Allah (blessings and peace be upon him) made the determination not to fast this day alone, but with another day [f: either before or after it], in order to be different from the People of the Book.
It has been reported in the Sahih of Imam Muslim (Allah have mercy on him), also from Ibn Abbas (Allah be pleased with him) that, “When the Messenger of Allah (blessings and peace be upon him) fasted the Day of `Ashura’ and ordered his companions to fast it, they said, ‘O Messenger of Allah! This is a day that the Jews and Christians venerate.’ So the Messenger of Allah (blessings and peace be upon him) said, ‘When next year comes – if Allah wills – we will fast the Ninth [of Muharram with it].’ But the next year did not come before the Messenger of Allah (blessings and peace be upon him) passed away.” [Muslim (1134), Abu Dawud (2445)]
And it is reported in the Musnad of Imam Ahmad (Allah have mercy on him), from Ibn Abbas (Allah be pleased with him) that the Prophet (Allah bless him and give him peace) said, “Fast the Day of `Ashura’ and be different from the Jews by fasting a day before it or a day after it.” [Ahmad]
Mourning on the 10th of Muharram is an Innovation
As for the mourning and grieving of the Shiah on this day because of the martyrdom of Sayyiduna Husayn ibn Ali (Allah be pleased with him and his father), this is of the actions of those whose actions in this life are misguided while they think that they are doing well. Neither Allah Most High nor His Messenger (Allah bless him & give him peace) commanded us to mourn on the days of the tribulations of the Prophets, or their deaths, let alone anyone else.
[The fuqaha have mentioned that it is an innovation to consider Muharram a month of mourning. It is not disliked to marry in this month.]
Some of the Virtues of the Day of `Ashura’
It is a day in which Allah forgave an entire people. Tirmidhi relates that the Prophet (Allah bless him and give him peace) said to a man, “If you want to fast a month after Ramadan, then fast Muharram, for it has a day in which Allah forgave an entire people, and He turns to others in repentance in.” [Tirmidhi (841)]