Ali ibn Jafar, from his brother Imam Musa ibn Ja’far عليه السلام, peace be upon them both, who said: I (narrator) asked Imam عليه السلام about ‘a man who sees the crescent moon in the month of Ramadan by himself, and no one else sees it. May he fast?’ Imam عليه السلام said: “If he does not doubt it, then let him fast; otherwise, let him fast with the people.”