Sahih Muslim
The Book of Fasting (Kitab Al-Sawm)
Book Number: 006 / Hadith Number: 2405
This hadith has been narrated by Sulaiman al-Taimi with the same chain of transmitters (but with a slight variation of words) that he (the Holy Prophet) said: The dawn is not like it as it is said; he then gathered his fingers and lowered them. But he said, it is like this (and he placed the index finger upon the other one and spread his hand).