The Prohibition on fasting in the second half of Sha’ban

Praise be to Allaah. 

Abu Dawood (3237), al-Tirmidhi (738) and Ibn Naajah (1651) narrated from Abu Hurayrah (may Allaah be pleased with him) that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “When Sha’baan is half over, do not fast.” Classed as saheeh by al-Albaani in Saheeh al-Tirmidhi, 590. 

This hadeeth indicates that it is not allowed to fast after halfway through Sha’baan, i.e., starting from the sixteenth day of the month. 

But there are reports that indicate that it is permissible to fast at this time. For example: 

Al-Bukhaari (1914) and Muslim (1082) narrated that Abu Hurayrah (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Do not anticipate Ramadaan by fasting one or two days before it begins, but if a man habitually fasts, then let him fast.” 

Fasting in Sha'ban

Shabaan is the name of the (eighth) month, and it is so called because in this month the Arabs used to disperse (tashaaba) in search of water, or it was said that they dispersed to carry out raids and forays. Or it was said
that it is so called because it shaaba (branches out or emerges) i.e., it appears between the months of Rajab and Ramadaan. The plural forms of the word Shabaan are Shabaanaat and Shaaabeen.

Fasting in Shabaan

Aaishah (may Allaah be pleased with her) said: The Messenger (saw) used to fast until we thought he would never break his fast, and not fast until we thought he would never fast. I never saw the Messenger of Allaah fasting for an entire month except in Ramadaan, and I never saw him fast more than he did in Shabaan. (Narrated by al-Bukhaari, no. 1833; Muslim, no. 1956).

According to a report narrated by Muslim (no. 1957). He used to fast all of Shabaan, he used to fast all but a little of Shabaan.