It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that a man came to the Prophet (peace and blessings be upon him) and said that he had come to his wife while she was menstruating. The Prophet (peace and blessings be upon him) ordered him "to give one dinar in charity, and if he does not find it, then half a dinar (in charity)". (b) Qatadah narrated it from al-Hakam as marfu', while Shu'bah narrates it from al-Hakam as mawquf; likewise Abu Abdullah al-Shaqari narrated it as mawquf, except that in his chain the narrator Abd al-Hamid is dropped.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1516