Sahih Muslim
The Book of Fasting (Kitab Al-Sawm)
Book Number: 006 / Hadith Number: 2410
Samura b. Jundub addressed and narrated from the Apostle of Allah (may peace be upon him) having said (these words): Neither the call of Bilal should mislead you nor this whiteness (of false dawn) till (the true) dawn appears (or he said) till the dawn breaks.