The Prophet [sallallaahu alaihi wa sallam] would prepare for Ramadan in the month of Shaban. It is narrated from Syeda Aisha that apart from Ramadan the month in which He [sallallaahu alaihi wa sallam] fasted the most was Shaban.
“The Prophet [sallallaahu alaihi wa sallam] would fast the most in the month of Shaban.”
One of the wisdoms in this practice mentioned is that in the month of Shaban is the night of Baraah (15th night) in which deeds are presented in the court of Allah, The Prophet [sallallaahu alaihi wa sallam] wanted his deeds to be presented in the state of fasting, just as has been mentioned in hadith.
However another wisdom in fasting in the month of Shaban mentioned by the Muhadditheen is that he prepared for Ramadan in the month of Shaban; because the month of Shaban is a forerunner for Ramadan its actions should also be those of Ramadan.
“In order to attain the barakah of Ramadan (this practice was to) ensure complete preparation and the satisfaction of the Nafs upon the complete obedience of Allah.”
In this way it is similar to the Sunnah prayers before the Fard. The Muslim uses the Sunnah prayers to turn his mind towards the court of Allah in preparation of the Fard prayer. The practice of the Sahaaba supports this reasoning. Syeduna Anas sheds light on the practice of the companions
“As soon as Shaban entered the Muslims would turn towards the Quran. They would also take Zakah out from their wealth and (by it) strengthen the poor and destitute for the fasts of Ramadan.”
Specific arrangements to sight the moon of the month of Shaban:
Fasting is based on the moon. Consequently the Prophet [sallallaahu alaihi wa sallam] made special arrangements to sight it. If the moon was sighted He [sallallaahu alaihi wa sallam] would fast and if it was not due to clouds etc. He [sallallaahu alaihi wa sallam] would fast only after completing thirty days of the month of Shaban.
Syeduna Abdullah bin Abi Qais narrates that he heard Umm ul Momineen Syeda Aisha say:
“The Prophet [sallallaahu alaihi wa sallam] used to safeguard the month of Shaban more than he safeguarded any other month.’
The Prophet [sallallaahu alaihi wa sallam] would order the companions to sight the moon and count it’s days. Syeduna Abu Hurayra states that the Prophet [sallallaahu alaihi wa sallam] would say to them:
“Count the moon of Shaban for Ramadan and do not mix it with Ramadan. Only he of you can fast who has fasted the day before.”