Hadith 1247

'Aishah (May Allah be pleased with her) reported: The Prophet (PBUH) did not observe voluntary Saum (fasting) so frequently during any other month as he did during Sha'ban. He observed Saum throughout the month of Sha'ban.

Another narration is: He (PBUH) observed Saum during the whole month of Sha'ban except a few days.

[Al- Bukhari and Muslim].