The middle of Shabaan should not be singled out for worshipThere is no saheeh marfoo‘ report that speaks of the virtue of the middle of Sha‘baan that may be followed, not even in the chapters on al-Fadaa‘il (chapters on virtues in books of hadeeth etc.).
Some maqtoo‘ reports (reports whose isnaads do not go back further than the Taabi‘een) have been narrated from some of the Taabi‘een, and there are some ahaadeeth, the best of which are mawdoo‘ (fabricated) or da‘eef jiddan (very weak).
These reports became very well known in some countries which were overwhelmed by ignorance; these reports suggest that people‘s lifespans are written on that day or that it is decided on that day who is to die in the coming year.
On this basis, it is not prescribed to spend this night in prayer or to fast on this day, or to single it out for certain acts of worship. One should not be deceived by the large numbers of ignorant people who do these things. And Allaah knows best. [Shaykh Ibn Jibreen]
If a person wants to pray qiyaam on this night as he does on other nights – without doing anything extra or singling this night out for anything – then that is OK. The same applies if he fasts the day of the fifteenth of Sha‘baan because it happens to be one of the ayyaam al-beed, along with the fourteenth and thirteenth of the month, or because it happens to be a Monday or Thursday.
If the fifteenth (of Sha‘baan) coincides with a Monday or Thursday, there is nothing wrong with that (fasting on that day), so long as he is not seeking extra reward that has not been proven (in the saheeh texts). And Allaah knows best. [Sheikh Muhammed Salih Al-Munajjid] - Islamqa
Which night is meant in, "Therein (that night) is decreed every matter of ordainments"
Also with regards to the night mentioned in the verses: ’We sent it (this Qur‘aan) down on a blessed night. Verily, We are ever warning [mankind that Our Torment will reach those who disbelieve in Our Oneness of Lordship and in Our Oneness of worship]. Therein (that night) is decreed every matter of ordainments“ [al-Dukhaan 44:3-4]
Ibn Jareer al-Tabari (may Allaah have mercy on him) said: the commentators differed concerning that night, i.e., which night of the year it is. Some of them said that it is Laylat al-Qadr, and it was narrated from Qurtaadah that it is Laylat al-Qadr. Others said that it is the night of the 15th of Sha‘baan. The correct view is the view of those who say that it is Laylat al-Qadr, because Allaah has told us of that when He says, …Verily, We are ever warning‘ [al-Dukhaan 44:3].“ (Tafseer al-Tabari, 11/221)
Status of the narrations concerning specifying worships on this day
What is narrated concerning the virtue of praying, fasting and worshipping on the fifteenth of Sha‘baan (al-nusf min Sha‘baan) does not come under the heading of da‘eef (weak), rather it comes under the heading of mawdoo‘ (fabricated) and baatil (false). So it is not permissible to follow it or to act upon it, whether that is in doing righteous deeds or otherwise.
A number of scholars ruled that the reports concerning that were false, such as Ibn al-Jawzi in his book al-Mawdoo‘aat, 2/440-445; Ibn Qayyim al-Jawziyyah in al-Manaar al-Muneef, no. 174- 177; Abu Shaamah al-Shaafa‘i in al-Baa‘ith …ala Inkaar al-Bida‘ wa‘l-Hawaadith, 124-137; al-…Iraaqi in Takhreej Ihyaa‘ …Uloom il-Deen, no. 582. Shaykh al-Islam [Ibn Taymiyah] narrated that there was consensus on the fact that they are false, in Majmoo‘ al-Fataawa, 28/138.
Shaykh Ibn Baaz (may Allaah have mercy on him) said in Hukm al-Ihtifaal bi Laylat al-Nusf min Sha‘baan (Ruling on celebrating the fifteenth of Sha‘baan):
And he (may Allaah have mercy on him) said:
Even if we assume that the hadeeth is da‘eef (weak) and not mawdoo‘ (fabricated), the correct scholarly view is that weak ahaadeeth should not be followed at all, even if they speak of righteous deeds or of targheeb and tarheeb (promises and warnings). The saheeh reports are sufficient and the Muslim has no need to follow the da‘eef reports. Nothing is known in Islam to suggest that this night or day is special, either from the Prophet (peace and blessings of Allaah be upon him) or from his companions.
The scholar Ahmad Shaakir said:
There is no difference between rulings or righteous deeds; we do not take any of them from da‘eef reports, rather no one hast he right to use any report as evidence unless it is proven to be soundly narrated from the Messenger of Allaah (peace and blessings of Allaah be upon him) in a saheeh or hasan hadeeth. [Al-Baa‘ith al-Hatheeth, 1/278. For more information, see: al-Qawl al-Muneef fi Hukm al-…Aml bi‘l-Hadeeth al-Da‘eef.]