Out of the holy months, Rajab and Sha'aban has a special importance which prepares servants of Allah in spirit and body for the month of Ramadan. The Prophet(PBUH) welcomed the 3 holy months joyfully praying as, "O Allah! Make the months of Rajab and Sha'aban blessed for us, and let us reach the month of Ramadan".
Another event which increases the value of the month of Rajab is Miraj (Ascension). Accourding to one argument, Miraj is thought to have happened in the month of Rajab, during which Our Prophet(Pbuh) went to Masjid Al-Aqsa from Masjid Al-Haram, then from there he ascended to the seven levels of heaven.
The Messenger of Allah cared about fasting when it was the month of Sha'ban. The son he loved a lot, had realised that and when he asked the reason that the Prophet did not fast in other months as much as he did in the month of Sha'ban, Prophet answered, "Sha'ban is a month between Rajab and Ramadhan, much neglected by people. In it, the actions of all servants are raised to the Lord of the Worlds; I love that my actions are not presented except that I am fasting."
THE NIGHT OF BERA'AT
The Prophet (saw) also said to Aishah (ra) to explain how merciful Allah is at this night, "Allah descends on the night of the middle of Sha’ban to the lowest heaven, and He forgives more than the numbers of hairs on the sheep of the Tribe Kalb (an Arab tribe renowned for their great flocks of sheep)" (Tirmizî, Savm, 39; İbn Mâce, İkâmet, 191)
Ramaḍân is the month in which the Quran was revealed as a guide for humanity with clear proofs of guidance and the standard ˹to distinguish between right and wrong˺. So whoever is present this month, let them fast. But whoever is ill or on a journey, then ˹let them fast˺ an equal number of days ˹after Ramaḍân˺. Allah intends ease for you, not hardship, so that you may complete the prescribed period and proclaim the greatness of Allah for guiding you, and perhaps you will be grateful. (2/Al-Baqarah, 185)
The messenger of Allah indicated the benefits of those who do Itikaf as follows: "He, stays away from sins and he is written good deeds about as a person who has done all the good deeds(in life)." (İbn Mâce, Sıyâm, 67)