“Rajab is the month of Allah, Sha`bān is my month and Ramadān is the month of my Nation.”

Az-Zamakhshari said: [Muharram’s] distinction among the sacred months is due to `Āshūra. The best of the months for the voluntary fast is Muharram, then Rajab then the rest of the sacred months and then Sha`bān.

‏The Prophet (S), when he entered the month of Rajab would say, “O Allah bless us in our Rajab and Sha`ban and cause us to reach Ramadan!” And on the night of Jum`ah he used to say, “This is the night of beauty and day of brightness.”‏ ‏

Abu Bakr ibn Abi Shaybah narrated that Abdullah ibn Nameer narrated and ibn Nameer narrated from his father that `Uthmān ibn Hakeem al-Ansaari narrated,  “I asked Sa`eed ibn Jubayr  about the fast of Rajab, what was his opinion on it. He said, ‘Ibn `Abbās narrated that the Prophet (S) used to fast until we said he would never break fast, and he used to break fast until we said he will never fast [again.]'”

Also narrated by `Uthmān ibn Hakeem from Muhammad ibn Ubayd

‏

The fast of the first day of Rajab is repentance for three years and the [fasting] second day is repentance for two years and the [fast of] third day is repentance for a year and then each [remaining] day is [repentance for] a month.

Abi Sa`eed related:

Rajab is one of the four forbidden months, [in which fighting is prohibited]. Its days are written on the Gates of the sixth heaven. When a man fasts one of its days and renews his fast with the fear and consciousness of Allah, Allah makes that gate to speak and makes that day to speak, saying, “O our Lord forgive him!”
And if he does not complete or perfect his fast with fear of Allah, they do not ask forgiveness for him and it is said, “your own self has betrayed you!”

From Ibn `Umar that the Prophet (S) said:

Whoever fasts the first day of Rajab it will be equivalent to the fast of one year; and whoever fasts seven days in it, the seven gates of Hell will be closed for him; and whoever fasts ten days from Rajab, a caller will call out from the sky, “Ask and you will be given!”

Abu Dharr related that the Prophet (S) said:

Whoever fasts a day of Rajab it will be equivalent to the fast of one month; and whoever fasts seven days in it the seven gates of Hell will be closed for him; and whoever fasts ten days from it, Allah will change all of his evil deeds into good ones; and whoever fasts from it eighteen days a caller will call out: Allah the Exalted has forgiven you; therefore renew your good deeds.

Anas related that the Prophet (S) said:

Rajab is a tremendous month in which Allah multiplies the good deeds. So whoever fasts a day from Rajab it is as if he fasted a year; and whoever fasts seven days of it the seven gates of Hell are closed to him; and whoever fasts eight days from it the eight  gates of Paradise are opened to him; and whoever fasts ten days from it will not ask Allah something except that Allah will grant it.

And whoever fasts from it fifteen days a caller will call out from heavens “Verily you have been forgiven whatever is past, so renew your good actions, for indeed your transgressions have been transformed into virtuous deeds.”

And whoever does more, Allah gives to him even more. And in Rajab, Allah carried Nuh (S) in the ark and he fasted and ordered all those with him to do so. And the ark sailed with them for six months until the first ten days of Muharram…”

Khalid az-Zeeyaat said:

It has reached us that on the first of Rajab, Nuh set sail in the ark and he fasted and ordered all those with him from Jinn and mankind to do so saying: Fast this day for verily whoever among you fasts it, will be brought far from the Fire the distance of one year’s travel; and whoever fasts seven days of it the seven gates of Hell are closed to him; and whoever fasts eight days from it the eight gates of Paradise are opened to him; and whoever fasts ten days from it will not ask Allah something except that Allah will grant it.

And whoever fasts from it fifteen days a caller will call out from heavens “Verily you have been forgiven whatever is past, so renew your good actions, whatever is past is forgiven.” And whoever does more, Allah gives to him even more.

Nuh fasted in the ark in Rajab, Sha`ban, Ramadan, Shawwal, Dhul-Q`idah and Dhul-Hijjah and ten days of Muharram. Then the ark came to rest on `Āshūra and Nuh said to all those who were with him from Jinn and humankind, “Fast this day.”

Saeed ibn Abi Rushd related that the Prophet (S) said:

Rajab is a tremendous month in which Allah multiplies the good deeds. So whoever fasts a day from Rajab it is as if he fasted a year; and whoever fasts seven days of it the seven gates of Hell are closed to him; and whoever fasts eight days from it the eight gates of Paradise are opened to him; and whoever fasts ten days from it will not ask Allah except that Allah will grant it. And whoever fasts from it fifteen days a caller will call out from heavens “Verily you have been forgiven whatever you have done in the past, so renew your good actions.”

And whoever does more, Allah gives to him even more. And in Rajab Allah carried Nūh in the ark for six months, the last of them being the day of `Āshūra, in which it landed on the mountain of Judee, and Nūh fasted along with all those with him as well as the animals, in thanks to Allah.”

Ibn `Abd al-Razzāq narrates that  Ibn `Umar said:

There are five nights in which invocation (du`a) is not rejected:  the first night of Rajab, the night of mid-Sha`ban, the night of Jum`a, and the night of [the `Eid of] Fitr and the night of [the `Eid of] Sacrifice..

‏Muhammad ibn Hātim informed us that Hibbān said that we were informed by Abdallāh from Shu`bah from Anas ibn Sirreen who said, I heard Abd al-Mālik ibn Abi al-Minhāl convey from his father that the Prophet (S) ordered them to fast the three “white” days. He said, “It is [equivalent] to fasting the entire month.”

Qays ibn ‘Abbaad said, “The tenth of Rajab is the day that Allah blots out or confirms what He pleases.”

Qays ibn ‘Abbaad said:

To Allah belongs the command on the tenth night of every sacred month. As for the tenth of the [month of] sacrifice, that is the Day of Sacrifice. As for the tenth of Muharram, that is the day of`Āshūra. As for the tenth of Rajab, in it [Allah revealed about it] “Allah doth blot out or confirm what He pleaseth.” [13:39] He said, “I forgot what he said regarding Dhul Qa`idah.”[the fourth sacred month]

 

Click Here for more about the sacred month of Rajab

[1] Abul-Fath ibn Abi Fawaris in his Amalee from al-Hasan (mursalan). Related by ad-Daylami and others from Anas (marfu`an) and Abi Shaykh from Abu Hurayrah and Abu Sa`eed (marfu`an) with the wording, “Verily the month of Ramadan is the month of my Nation.” However Ibn al-Jawzi in his Mawdu`at (Forgeries) related it through many different ways, as did al-Hafiz Ibn Hajar in Kitab tabayyin al-`ajab feemaa warada fee rajab.
[2] Related by Ibn Asakir, al-Bazaar and at-Tabarani in al-Awsat, and by al-Bayhaqi in Shu`ab al-Iman from Anas, who graded it weak.
[3] Related in Sahih Muslim.
[4] Abu Muhammad al-Khalal in Virtues of Rajab, from Ibn `Abbās.
[5] Abu Muhammad al-Hassan ibn Muhammad al-Khalal.
[6] Abu Na`eem and Ibn Asakir.
[7] Al-Khateeb.
[8] Related by al-Bayhaqi from Anas.
[9] Related by Ibn Asakir.
[10] Related by At-Tabarani.
[11] Al-Musannaf 4:317.
[12] An-Nisa’ee. The “white” days are the three days in the middle of the month: 13th, 14th, 15th, so-named for the brightness due to the full moon in their nights.
[13] Related by Ibn Jareer.
[14] Related by Ibn Mundhir and Ibn Abi Haatim and Bayhaqi in Shu`ab al-Iman.

Reposted from sunnah.org.