Kuraib reports: Lady Umm al-Fadl bint al-Harith (may Allah be pleased with her) sent me to the service of Sayyiduna Muawiyah (may Allah be pleased with him). He says: I came to Syria, fulfilled the task of Umm al-Fadl, and during that time the crescent of Ramadan was sighted. I was present in Syria; I saw the crescent on the night of Friday. Then, at the end of the month, I came to Madinah Munawwarah. Sayyiduna Abdullah ibn Abbas (may Allah be pleased with them both) spoke with me, and when I mentioned the sighting of the crescent, he asked: When did you see the crescent? I replied: I saw it on the night of Friday. Sayyiduna Abdullah ibn Abbas (may Allah be pleased with them both) asked: Did you see it yourself? I said: Yes! And the people also saw it, and I fasted, and Sayyiduna Muawiyah (may Allah be pleased with him) also fasted. Sayyiduna Abdullah ibn Abbas (may Allah be pleased with them both) said: "We saw it on the night of Saturday, and we will continue to fast until we complete thirty days or see the crescent of Shawwal." So I said to him: Is the sighting of the crescent and fasting of Sayyiduna Muawiyah (may Allah be pleased with him) not sufficient for you? He replied: No! The Noble Prophet (peace and blessings be upon him) has given us this instruction. This narration is authentic.