ذِكْرُ الْبَيَانِ بِأَنَّ تَرْكَ الِاغْتِسَالِ مِنَ الْإِكْسَالِ كَانَ ذَلِكَ فِي أَوَّلِ الْإِسْلَامِ، ثُمَّ أُمِرَ بِالِاغْتِسَالِ مِنْهُ بَعْدُ
The verdict that water (bath) is necessary when there is emission given by the people (in the early days of Islam) was due to the concession granted by the Messenger of Allah in the beginning of Islam. He then commanded to take a bath (in such a case). Abu Dawud said : By Abu Ghassan is meant Muhammad b. mutarrif. (Using translation from Abū Dāʾūd 215)
«أَنَّ الْمَاءَ مِنَ الْمَاءِ كَانَ رُخْصَةً رَخَّصَهَا رَسُولُ اللَّهِ ﷺ فِي أَوَّلِ الزَّمَانِ أَوْ بَدْءِ الْإِسْلَامِ ثُمَّ أَمَرَ بِالِاغْتِسَالِ بَعْدُ»