Sahih Al Bukhari Hadith Number 888

Narrated Anas: Allah’s Messenger (peace be upon him) said, “I have told you repeatedly to use the Siwak. (The Prophet (peace be upon him) put emphasis on the use of the Siwak.)

11  Friday Prayer
Hadith number 888
Volume no 2
Chapter: 8 (To clean the teeth with Siwak on Friday)