Abu Bakr says: I heard Abu Hurayrah (may Allah be pleased with him) saying in his sermons: Whoever wakes up in the morning in a state of janabah should not fast. I mentioned this to Abd al-Rahman, and he rejected it. Then Abd al-Rahman and I went to Sayyidah Aishah and Umm Salamah (may Allah be pleased with them both), and Abd al-Rahman asked them about this, and both of them said that the Messenger of Allah (peace and blessings be upon him) would wake up in the morning in a state of janabah from intercourse, not from a wet dream, and then he (peace and blessings be upon him) would fast. Then we came to Marwan, and Abd al-Rahman told him the whole matter. Marwan (may Allah be pleased with him) said: I urge you strongly to go to Abu Hurayrah (may Allah be pleased with him) and refute what he says. He says: Then we came to Abu Hurayrah (may Allah be pleased with him), and Abu Bakr was with us throughout the whole matter. Abd al-Rahman stated this before Abu Hurayrah (may Allah be pleased with him), and Abu Hurayrah (may Allah be pleased with him) said: I heard this from al-Fadl bin Abbas (may Allah be pleased with him); I did not hear it from the Prophet (peace and blessings be upon him). So Abu Hurayrah (may Allah be pleased with him) retracted what he used to say. I said to Abd al-Malik: Did the two of them mention Ramadan? He said: Like that; he (peace and blessings be upon him) would wake up in the morning in a state of janabah, not from a wet dream, and then fast.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 7996