Question: What is the status of fasting on the day of Arafah?

Answer: It is Mustahab (Highly Recommend) to fast on the day of Arafah (the 9th of Dhul Hijjah).

Nabi Sallallahu Alaihi Wasallam said; “Fasting on the Day of Arafah expiates the sins of two years: the previous year and the coming year.” [Muslim]
وأما المندوب ....كل صوم ثبت طلبه والوعد عليه بالسنة ( حاشية الطحطاوي ٥٢٨ )

And Allah Knows Best

Yusuf Moosagie