Jami` at-Tirmidhi 1880
جامع الترمذي#1880SahihNarrated Ibn 'Umar: "We would eat during the time of the Messenger of Allah (ﷺ) while we were walking, and we would drink while we were standing." [Abu 'Eisa said:] This Hadith is Hasan Sahih Gharib as a narration of 'Ubaidullah bin 'Umar, from Nafi', from Ibn 'Umar. 'Imran bin Hudair reported this Hadith from Abu Al-Bazari, from Ibn 'Umar. Abu Al-Bazari's name is Yazid bin 'Utarid
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiSahih
In-book reference: 26:20