Sahih Bukhari
Sahih Bukhari Volume 002, Book 022, Hadith Number 292.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 22. Actions While Praying
Narated By Zaid bin Arqam : In the life-time of the Prophet we used to speak while praying, and one of us would tell his needs to his companions, till the verse, 'Guard strictly your prayers (2.238) was revealed. After that we were ordered to remain silent while praying.