Hadith 7178
Narrated Muhammad bin Zaid bin `Abdullah bin `Umar: Some people said to Ibn `Umar, "When we enter upon our ruler(s) we say in their praise what is contrary to what we say when we leave them." Ibn `Umar said, "We used to consider this as hypocrisy."
Hadith 7179
Narrated Abu Huraira: Allah's Apostles said, "The worst of all mankind is the double-faced one, who comes to some people with one countenance and to others, with another countenance."