Ibrahim bin Abd al-Rahman said: I asked Asim al-Ahwal about the miswak for a fasting person, and he said: There is no harm in it. I said: With both a fresh and a dry one? He said: Do you think it is moister than water? I said: From whom did you hear it? He said: From Sayyiduna Anas bin Malik (may Allah be pleased with him), from the Prophet (peace and blessings be upon him).
Abu Ahmad (Ibn Adi) said: Most of the hadiths of this Ibrahim are not preserved (ghayr mahfuzah).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8328