Mishkat al-Masabih 3 Purification كتاب الطهارة 249

وَعَنِ ابْنِ عَبَّاسٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا وَقَعَ الرَّجُلُ بِأَهْلِهِ وَهِيَ حَائِضٌ فَلْيَتَصَدَّقْ بِنِصْفِ دِينَارٍ» . رَوَاهُ التِّرْمِذِيّ وَأَبُو دَاوُد النَّسَائِيّ والدارمي وَابْن مَاجَه

Ibn ‘Abbas reported God’s messenger as saying, “When a man has intercourse with his wife while she is menstruating, he must give half a dinar in alms.’ Tirmidhi, Abu Dawud, Nasa’i, Darimi and Ibn Majah transmitted it.