احسن الله إليك Is it a must to complete the Ramadan fasts in order to fast the day of Arafat?

Ibn ʿUthaymīn (may Allah have mercy on him) said: “If the ten days of Dhul-Ḥijjah or the Day of ʿArafah pass by a person, we say: make up the missed fasts during these days. You may attain both the reward of making up the obligatory fast and the reward of fasting these virtuous days. And even if one assumes that the reward of fasting these days is not obtained while making up missed fasts, then fulfilling the obligation (of making up missed fasts) is still superior to offering voluntary fasts.”