He informed him that the Jews would never be satisfied with him until he adopted their direction of prayer, and He further warned that if he were to follow their whims after knowledge had come to him, he would have neither protector nor helper from Allah. The Almighty also said, “For each is a direction toward which he turns” (al-Baqarah 2:148). In another verse He declared that He has appointed for every community a law and a clear way; distinctive symbols of worship, therefore, form part of the revealed law.

This becomes evident in the case of the very day of ʿĀshūrāʾ, which the Prophet fasted while saying, “We have a stronger claim to Moses than you.” Shortly before his death, however, he legislated that Muslims should differ from the Jews in observing this fast and expressly commanded them to do so. For that reason Ibn ʿAbbās (may Allah be pleased with them both)—the Companion who reported the words, “He liked to agree with the People of the Book in matters about which he had received no command,” and who also transmitted, “We have a stronger claim to Moses than you”—was among the most insistent of all the Companions that Muslims distinguish themselves from the Jews in fasting ʿĀshūrāʾ. As noted earlier, he is the one who transmitted the ruling that this difference is prescribed.

Muslim likewise relates in his Ṣaḥīḥ from al-Ḥakam ibn al-Aʿraj, who said: “I came to Ibn ʿAbbās while he was reclining on his cloak at Zamzam and asked him, ‘Tell me about fasting the day of ʿĀshūrāʾ.’ He answered, ‘When you sight the crescent of Muḥarram, count the days, and on the morning of the ninth…’”