The Messenger of Allah ﷺ said, "Eat olive oil and anoint yourselves with it, for it comes from a blessed tree."
حدثنا يحيى بن موسى حدثنا عبد الرزاق عن معمر عن زيد بن أسلم عن أبيه
قال رسول الله ﷺ كلوا الزيت وادهنوا به فإنه من شجرة مباركة
[Its chain of transmission is sahih]. Ibn Majah also narrated it in the Book of Foods, chapter on Oil, hadith no. 3319, from the hadith of Abdul-Razzaq through this same route. Hakim graded it sahih according to the criteria of the two Shaykhs (Bukhari and Muslim), 4/122, and Dhahabi agreed with him. Diya also included it in Al-Mukhtarah.The hadith of Abdul-Razzaq, from Mamar, from Zayd bin Aslam, from his father, is found in his Musannaf, 10/422, hadith no. 19568. This hadith has many corroborating narrations.