It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the people were in doubt about the new moon of Ramadan, and they intended (since it had not been confirmed) neither to perform the night prayer nor to fast. Meanwhile, a Bedouin came from the area of al-Harrah and testified that he had seen the new moon. So the Prophet (peace and blessings be upon him) ordered Sayyiduna Bilal (may Allah be pleased with him), and he called out among the people that they should both perform the night prayer and fast. Imam Bukhari used the hadiths of Ikrimah as evidence, and Imam Muslim used the hadiths of Simak bin Harb and Hammad bin Salamah as evidence; this hadith is sahih, but the two Shaykhs did not record it.