Sahih al-Bukhari 674
Sahih al-Bukhari · Book 10: Call to Prayers (Adhaan) · (What should one do) if the meal has been served and the Iqama has been pronounced for As-Salat(the prayer)
Narrated Ibn `Umar:
وَقَالَ زُهَيْرٌ وَوَهْبُ بْنُ عُثْمَانَ عَنْ مُوسَى بْنِ عُقْبَةَ ، عَنْ نَافِعٍ ، عَنِ ابْنِ عُمَرَ ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم " إِذَا كَانَ أَحَدُكُمْ عَلَى الطَّعَامِ فَلاَ يَعْجَلْ حَتَّى يَقْضِيَ حَاجَتَهُ مِنْهُ، وَإِنْ أُقِيمَتِ الصَّلاَةُ ". رَوَاهُ إِبْرَاهِيمُ بْنُ الْمُنْذِرِ عَنْ وَهْبِ بْنِ عُثْمَانَ ، وَوَهْبٌ مَدِينِيٌّ .
The Prophet (ﷺ) said, "If anyone of you is having his meals, he should not hurry up till he is; satisfied even if the prayer has been started."