Jami` at-Tirmidhi, Volume 3, Book 24, Hadith 1883 (DarusSalam) ⓘ
Narrated 'Amr bin Shu'aib: From his father, from his grandfather who said: "I saw the Messenger of Allah drinking while standing and sitting." [Abu 'Eisa said:] This Hadith is Hasan Sahih.
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، عَنْ حُسَيْنٍ الْمُعَلِّمِ، عَنْ عَمْرِو بْنِ شُعَيْبٍ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، قَالَ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَشْرَبُ قَائِمًا وَقَاعِدًا . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ .
also referenced under: Hadith 1883 (Reference) & Book 26, Hadith 23 (In-Book)