They were once uncertain about the crescent moon of Ramadan and intended neither to perform the night prayer nor to fast. Then an Arabi came from al-Harrah and testified that he had seen the crescent. He was brought to the Prophet ﷺ, who asked him, "Do you bear witness that there is no god but Allah and that I am the Messenger of Allah?"He replied, "Yes," and testified that he had seen the crescent.So the Prophet ﷺ ordered Bilal to announce to the people that they should perform the night prayer and observe the fast.
حدثني موسى بن إسمعيل حدثنا حماد عن سماك بن حرب
أنهم شكوا في هلال رمضان مرة فأرادوا أن لا يقوموا ولا يصوموا فجاء أعرابي من الحرة فشهد أنه رأى الهلال فأتي به النبي ﷺ فقال أتشهد أن لا إله إلا الله وأني رسول الله قال نعم وشهد أنه رأى الهلال فأمر بلالا فنادى في الناس أن يقوموا وأن يصوموا
No references are available.
[Its chain of transmission is daif] Nasai narrated it in the Book of Fasting, in the chapter on accepting the testimony of a single man regarding the sighting of the new moon of Ramadan, etc., hadith no. 2116, from the hadith of Simak, through this route, and he said, "It is mursal." See also the previous hadith, no. 2340.