Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) forbade hastening the month of Ramadan by fasting one or two days, except for a person who was already fasting and this day coincided with his fasts.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 7963
Sayyidah Aishah (may Allah be pleased with her) said that the Messenger of Allah (peace and blessings be upon him) did not fast any month of the year except Sha'ban; he used to fast the whole of Sha'ban.
Sayyidah Aishah (may Allah be pleased with her) said: I did not see him (peace and blessings be upon him) fasting more in any month than in Sha'ban. In one narration it states that he used to fast the whole of Sha'ban; it is also stated that he (peace and blessings be upon him) left only a few fasts of Sha'ban, rather he fasted the whole of Sha'ban.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 7964
Sayyidah Umm Salamah (may Allah be pleased with her) said that the Prophet (peace and blessings be upon him) did not fast two months together except Sha'ban and Ramadan. In the hadith of Sufyan, Umm Salamah (may Allah be pleased with her) said: I did not see the Messenger of Allah (peace and blessings be upon him) fasting two consecutive months, except that he (peace and blessings be upon him) would join Sha'ban to Ramadan.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 7965
Sayyidah Umm Salamah (may Allah be pleased with her) said that the Prophet (peace and blessings be upon him) did not fast a complete month in the year except Sha'ban, which he would join to Ramadan.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 7966