مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3121
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn ‘Abbas (رضي الله عنه) that A man had intercourse with his wife when she was menstruating. He asked the Messenger of Allah (ﷺ) about that and he told him to give a dinar or half a dinar in charity.
Musnad Ahmad 3145Saheeh mawqoof]