A man once asked ‘Alī – Allāh be pleased with him – about taking a full bath (ghusl). He replied, “Wash every day if you want.” The man said, “No, what I mean is the ghusl.” ʿAli replied, “Al-Jumu’ah (Friday), the Day of ‘Arafah, the Day of Al-Naḥr (sacrificial slaughter, ‘Eid al-Adhā) and the Day of Al-Fiṭr (the ‘Eid following Ramaḍān).”

Al-Bayhaqī, Al-Sunan Al-Kubrā, ḥadīth #6343. In Irwā Al-Ghalīl, under ḥadīth #146, Shaykh Al-Albānī graded its chain of transmission ṣaḥīḥ and said this is the best evidence for the recommendation to bath on the two ‘Eid celebrations.