Sahih al-Bukhari Book 10, Hadith 66
Allah's Messenger (ﷺ) said, "If the supper is served start having it before praying the Maghrib prayer and do
not be hasty in finishing it."
The Prophet (ﷺ) said, "If supper is served, and Iqama is pronounced one should start with the supper."
Ibn `Umar said, "Allah's Messenger (ﷺ) said, 'If the supper is served for anyone of you and the Iqama is pronounced, start with the supper and don't be in haste (and carry on eating) till you finish it." If food was served for Ibn `Umar and Iqama was pronounced, he never came to the prayer till he finished it (i.e. food) in spite of the fact that he heard the recitation (of the Qur'an) by the Imam (in the prayer).