It has been narrated on the authority of Hadhrat Anas bin Malik (May Allah be well pleased with him), he said that the Holy Prophet (Sallallahu alaihi wasallam) among the great months of Allah (Subhanahu wa Ta’ala) is the month of Rajab and that is the month of Allah (Subhanahu wa Ta’ala). The one who respects and reveres Rajab verily reveres the commands of Allah (Subhanahu wa Ta’ala) and Allah (Subhanahu wa Ta’ala) will enter the person into Jannah who reveres His command and will grant him His pleasure.
Sha’abaan is My month. Whoever reveres Sha’abaan verily reveres My command and whoever respects My command, on the day of the Qiyamah, I will be the his helper and a source of good for him.
Ramadhan is the month of My Ummah. Whoever respects Ramadhan and maintains its sanctity and does not violate it and fasts in its days and stands up in worship in its nights and saves his organs, that person will come out of Ramadhan in such a state that there will no sin on him for which Allah (Subhanahu wa Ta’ala) will call him to account.
(Baihaqi, Shu’abul Iman, Hadith No: 3652, Kanz Ul ‘Ummal, Hadith No: 35216)

Hadith related from the Companion Abdullah b.’Amr (May Allaah be pleased with him) which says that the Prophet(Sallalahu Alaihi Wassalam) said: “Allah looks at His creation during the night of the

15th of Sha’ban and He forgives His servants except two- one intent on hatred (mushanin) and a murderer (qatilu nafs). ( Ref : Musnad Ahmad 2/176 #6642. Al-Bazzar also related this Hadith and he classified it as ‘hasan’. )

Imam Suyuti (Rh)says in his Haqiqat al-sunna wa al-bid`a:“As for the night of mid-Sha`ban, it has great merit and it is desirable (mustahabb) to spend part of it in supererogatory worship.” ( Ref: Suyuti, Haqiqat al-sunna wa al-bid`a aw al-amr bi al-ittiba` wa al-nahi `an al-ibtida` (1405/1985 ed.) p. 58. He adds: “However, this must be done alone, not in congregation.”)

The leader of all saints, Hadhrat Shaykh Abdul Qadir Jilani (May Allah sanctify his soul) says
about the secret meanings hidden in the word “Sha’abaan”:
There are five letters in the word “Sha’abaan” (i.e. in the Arabic word):
The Arabic “Sheen,” which stands “Sharaf” i.e. honor.
“’Ain,” which stands for “’Ulu” i.e. elevation.
“Ba” which stands for “birr” i.e. virtuousness.
“Alif” which stands for “Ulfat” i.e. love
“Noon” which stands for “Noor” i.e. radiance, light.

These letters indicate that in the month of Sha’abaan, the worshippers of Allah (Subhanahu wa Ta’ala) are granted these bounties by Allah (Subhanahu wa Ta’ala).

Hadhrat Ghouse Azam Dastagir (May Allah be well pleased with him) points out the temporary nature of this world and the changing of times and says about the importance of the month of Sha’abaan in these words:

Life has 3 states:

The past state, the present state and the future state.

 In the same way, there are 3 months: Rajab, which has passed and will not return and

Ramadhan, which we are waiting for. We do not know whether we will be alive to get it

or not and Sha’abaan is the link between these 2 months.

We should consider obedience to Allah (Subhanahu wa Ta’ala) as a respipte (Ghaneemat)
(Ghuniya Lit talibi tariqil haqqi, Vol. 1, Pg No: 188)

The verse of Durud was revealed in this month and the command for Durud was given to us, so for this reason we are asked to send a lot of Durud on the Holy Prophet (Sallallahu alaihi wa sallam) in this month. As given in Ghuniya Lit talibi  tariqil haqqi, Vol. 1, Pg No:188:

The Holy Prophet (Sallallahu alaihi wa sallam) would fast for the whole of Sha’abaan. When I asked Him, He (Sallallahu alaihi wa sallam) said: Allah (Subhanahu wa Ta’ala) writes (the names of) all those who would die in this year in this night. I desire that My time of passing away should be when I am fasting. The Holy Prophet (Sallallahu alaihi wa sallam) said: This is that month between Rajab and Ramadhan, which people do not think about and this is the month in which deeds (a’amaal) are presented before Allah (Subhanahu wa Ta’ala), so I want that I should be fasting and My deeds should be presented before Allah (Subhanahu wa Ta’ala).(Sunan Nasai, Vol. 1, Pg No: 321. Hadith No: 2317, Musnad Imam Ahmed, Musnad UlAnsaar, Hadith No: 20758)

All good is from Allah Ta’ala whereas mistakes are from this humble speck. May Allah Ta’ala Bless all readers, bringing you all closer to Him and His Rasul SallAllahu alaihi wasallam. May He accept our humble efforts and grant us the capacity to be good and do good. Ameen.

wassalam