Language:
كتاب الاستئذان
79  
Asking Permission
(32)
Chapter: "When you are told to make room in the assemblies, make room..."
(32)
بَابُ: {إِذَا قِيلَ لَكُمْ تَفَسَّحُوا فِي الْمَجَالِسِ فَافْسَحُوا يَفْسَحِ اللَّهُ لَكُمْ وَإِذَا قِيلَ انْشِزُوا فَانْشِزُوا} الآيَةَ
Sahih al-Bukhari 6270

Narrated Ibn `Umar:

The Prophet (ﷺ) forbade that a man should be made to get up from his seat so that another might sit on it, but one should make room and spread out. Ibn `Umar disliked that a man should get up from his seat and then somebody else sit at his place.

حَدَّثَنَا خَلاَّدُ بْنُ يَحْيَى، حَدَّثَنَا سُفْيَانُ، عَنْ عُبَيْدِ اللَّهِ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ نَهَى أَنْ يُقَامَ الرَّجُلُ مِنْ مَجْلِسِهِ وَيَجْلِسَ فِيهِ آخَرُ، وَلَكِنْ تَفَسَّحُوا وَتَوَسَّعُوا‏.‏ وَكَانَ ابْنُ عُمَرَ يَكْرَهُ أَنْ يَقُومَ الرَّجُلُ مِنْ مَجْلِسِهِ، ثُمَّ يُجْلِسَ مَكَانَهُ‏.‏
Reference : Sahih al-Bukhari 6270
In-book reference : Book 79, Hadith 44
USC-MSA web (English) reference : Vol. 8, Book 74, Hadith 287
  (deprecated numbering scheme)