Language:
كتاب الأحكام
93  
Judgments (Ahkaam)
(27)
Chapter: Praising the Sultan and saying differently after leaving him
(27)
باب مَا يُكْرَهُ مِنْ ثَنَاءِ السُّلْطَانِ، وَإِذَا خَرَجَ قَالَ غَيْرَ ذَلِكَ
Sahih al-Bukhari 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."

حَدَّثَنَا أَبُو نُعَيْمٍ، حَدَّثَنَا عَاصِمُ بْنُ مُحَمَّدِ بْنِ زَيْدِ بْنِ عَبْدِ اللَّهِ بْنِ عُمَرَ، عَنْ أَبِيهِ، قَالَ أُنَاسٌ لاِبْنِ عُمَرَ إِنَّا نَدْخُلُ عَلَى سُلْطَانِنَا فَنَقُولُ لَهُمْ خِلاَفَ مَا نَتَكَلَّمُ إِذَا خَرَجْنَا مِنْ عِنْدِهِمْ قَالَ كُنَّا نَعُدُّهَا نِفَاقًا‏.‏
Reference : Sahih al-Bukhari 7178
In-book reference : Book 93, Hadith 41
USC-MSA web (English) reference : Vol. 9, Book 89, Hadith 289
  (deprecated numbering scheme)