The ruling on fasting the day of Ashura without fasting the day before or the day after

Question:
A person fasted the day of Ashura, but did not fast the day before it or the day after it. What is the ruling? May Allah reward you with good.

Answer:
The well-known view among scholars is that it is disliked (makruh); because the Prophet (peace and blessings be upon him) said regarding the latter: , and likewise, after being forbidden from imitating the People of the Book, he initially loved to agree with them in matters where he had not been forbidden, and he used to fast only on the Day of Ashura. Then Allah commanded him to differ from the polytheists and not to agree with them, so he said: , but he did not live to do so. And Ibn Abbas, the narrator of the hadith, said: "He fasts on the ninth and the tenth."
Ahmad and others narrated from the Prophet (peace and blessings be upon him) that he said: , and in another wording: , but there is weakness in its chain of narration; because it is from the narration of Muhammad ibn Abi Layla, and he is considered weak in hadith, but it has corroborating narrations in meaning.
So the Sunnah according to the people of knowledge is to fast a day before it, or a day after it, or to fast what is before it and what is after it—three days—this is the Sunnah for all, so as not to conform to the People of the Book.