Sahih Bukhari | Volume 8 | Hadith Number 409

Narrated by Abu Huraira
Abu-l-Qasim (the Prophet) said, "On Friday there is a particular time. If a Muslim happens to be praying and invoking Allah for something good during that time, Allah will surely fulfil his request." The Prophet pointed out with his hand. We thought that he wanted to illustrate how short that time was.