Testimony to sighting the new moon of Ramadan

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said that a Bedouin came to the Prophet (peace and blessings be upon him) and said: I have seen the crescent of Ramadan. He (peace and blessings be upon him) said: "Do you bear witness that there is no god but Allah?" He said: Yes. He (peace and blessings be upon him) said: "Do you affirm that Muhammad (peace and blessings be upon him) is the Messenger of Allah?" He said: Yes. He (peace and blessings be upon him) said: "O Bilal, announce among the people that they should fast tomorrow."

Al-Walid bin Abi Thawr (may Allah have mercy on him) narrated a similar hadith from Simak, except that he did not say: "the crescent of Ramadan."

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said that a Bedouin came to the Prophet (peace and blessings be upon him) on the night of the crescent of Ramadan and said: O Messenger of Allah, I have seen the crescent. He (peace and blessings be upon him) said: "Do you bear witness that there is no god but Allah and that I am the Messenger of Allah?" He said: Yes. He (peace and blessings be upon him) said: "Then fast."
It was likewise narrated from Abu Asim from al-Thawri as connected (mawsul), while others narrated it from al-Thawri as mursal.

Simak narrated from Ikrimah (may Allah have mercy on him) that once there was doubt about the crescent of Ramadan, and they decided that they would neither pray at night nor fast. Then a Bedouin came from the Harrah and testified that he had seen the crescent. He was brought to the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Do you affirm 'La ilaha illallah' (there is no god but Allah) and 'anni Rasulullah' (that I am the Messenger of Allah)?" He said: Yes, and he affirmed that he had seen the crescent. So he (peace and blessings be upon him) ordered Bilal (may Allah be pleased with him), and he announced that the people should pray at night and fast. [Sahih. Recorded by Abu Dawud]
Abu Dawud said: A group narrated it from Simak from Ikrimah as mursal, and no one mentioned the night prayer except Hammad bin Salamah. The Shaykh said: Abu Dawud narrated the hadith of Hammad from Musa from Hammad as mursal.

Simak narrates from Ikrimah (may Allah have mercy on him) that Ibn Abbas (may Allah be pleased with him) narrated this hadith, except that he did not mention "once" (marrah).

Abu Bakr bin Nafi' (may Allah have mercy on him) narrates from his father, and he from Ibn Umar (may Allah be pleased with him), that the people looked for the new moon, and I informed the Messenger of Allah (peace and blessings be upon him) that I had seen it, so he (peace and blessings be upon him) fasted and ordered the people to fast.
Ali bin Umar al-Hafiz said: Marwan bin Muhammad is alone in narrating it from Ibn Wahb, and he is thiqah (trustworthy). This hadith is counted among the solitary narrations of Marwan bin Muhammad al-Dimashqi.

Abdullah bin Wahb (may Allah have mercy on him) says: Yahya informed me, and he mentioned a similar hadith, except that he said: The Messenger of Allah (peace and blessings be upon him) "fasted and ordered the people to fast."

Hafs bin Umar (may Allah have mercy on him) says that Abu Awanah and Mis'ar narrated a similar hadith. This is a narration that should not be used as evidence, and what has preceded is sufficient.

Muhammad bin Abdullah bin Amr bin Uthman (may Allah have mercy on him) narrates from his mother, Fatimah bint Husayn (may Allah be pleased with her), that a man testified before Ali (may Allah be pleased with him) to sighting the new moon of Ramadan, so he fasted; and I think he said: and he ordered the people to fast. And he said: "Fasting a day of Sha'ban is dearer to me than leaving a fast of Ramadan."