عَنْ عَبْدِ اللَّهِ بْنِ أَبِي قَيْسٍ أَنَّهُ سَمِعَ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا تَقُولُ: كَانَ أَحَبَّ الشُّهُورِ إِلَى رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ أَنْ يَصُومَهُ شَعْبَانُ، ثُمَّ يَصِلُهُ بِرَمَضَانَ
It is narrated from Sayyidah Aisha (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) loved to observe voluntary fasts most in the month of Sha'ban; he (peace and blessings be upon him) would fast in this month and join it with the month of Ramadan.