A man once asked ‘Alî – Allâh 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.” ‘Ali replied, “Al-Jumu’ah (Friday), the Day of ‘Arafah, the Day of Al-Nahr (sacrificial slaughter, ‘Eid al-Adhâ) and the Day of Al-Fitr (the ‘Eid following Ramadân).”

Al-Bayhaqî, Al-Sunan Al-Kubrâ, hadîth #6343. In Irwâ Al-Ghalîl, under hadîth #146, Shaykh Al-Albânî graded its chain of transmission sahîh and said this is the best evidence for the recommendation to bath on the two ‘Eid celebrations.