Sahih Bukhari
Punishment of Disbelievers at War with Allah and His Apostle
Volume: 008 / Book Number: 082 / Hadith Number: 818
Narrated Zaid bin Khalid Al-Jihani:
I heard the Prophet ordering that an unmarried person guilty of illegal sexual intercourse be flogged one-hundred stripes and be exiled for one year. Umar bin Al-Khattab also exiled such a person, and this tradition is still valid.