The tongue is small, but can lead to immense calamities. The two most difficult body parts to protect and avert from sin are the tongue and the private parts – so much so that our beloved Prophet – Allah bless him and give him peace – said:
“Whosoever gives me a guarantee to safeguard what is between his jaws and what is between his legs, I shall guarantee him Jannah.” (Bukhari)
What is between his jaw refers to the tongue; both what it expresses and what it consumes. What is between the legs refers to the private parts. When the believer protects his tongue from the vices of the tongue, the reward is nothing but paradise.