Sahih Bukhari
Punishment of Disbelievers at War with Allah and His Apostle
Volume: 008 / Book Number: 082 / Hadith Number: 799
Narrated Sahl bin Sa'd:
The Prophet said, "Whoever guarantees me (the chastity of) what is between his legs (i.e. his private parts), and what is between his jaws (i.e., his tongue), I guarantee him Paradise."