‘Amr b. Shu'aib, on his father’s authority, said his grandfather told that he saw God’s messenger drink both standing and sitting. Tirmidhi transmitted it.

وَعَنْ عَمْرِو بْنِ شُعَيْبٍ عَنْ أَبِيهِ عَنْ جده قَالَ: رَأَيْت رَسُول لله صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَشْرَبُ قَائِمًا وَقَاعِدًا. رَوَاهُ التِّرْمِذِيّ