Language:
كتاب الأذان
10  
Call to Prayers (Adhaan)
(42)
Chapter: (WHat should one do) if the meal has been served and the Iqama has been pronounced for As-Salat(the prayer)
(42)
باب إِذَا حَضَرَ الطَّعَامُ وَأُقِيمَتِ الصَّلاَةُ
Sahih al-Bukhari 671

Narrated `Aisha:

The Prophet (ﷺ) said, "If supper is served, and Iqama is pronounced one should start with the supper."

حَدَّثَنَا مُسَدَّدٌ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ هِشَامٍ، قَالَ حَدَّثَنِي أَبِي قَالَ، سَمِعْتُ عَائِشَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ قَالَ ‏ "‏ إِذَا وُضِعَ الْعَشَاءُ وَأُقِيمَتِ الصَّلاَةُ فَابْدَءُوا بِالْعَشَاءِ ‏"‏‏.‏
Reference : Sahih al-Bukhari 671
In-book reference : Book 10, Hadith 65
USC-MSA web (English) reference : Vol. 1, Book 11, Hadith 640
  (deprecated numbering scheme)