Sayyiduna Ammar bin Yasir (may Allah be pleased with him) says: The Prophet (peace and blessings be upon him) would not eat from a gift until he had ordered the one who brought it to eat from it, because of the sheep that was given to him as a gift at Khaybar.
Al-Bazzar and Tabarani recorded it, and Tabarani's narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأطعمة / 7900