Samurah said: “The Messenger of Allah صلی اللہ علیہ وآلہ وسلم said: ‘Do not be confused by the Adhan of Bilal, or by this whiteness, until dawn appears like this” — meaning horizontally. (One of the narrators) Abu Dawud said: “And he spread out his hands gesturing to the right and left.” (Sahih)