When Banu Qurayzah agreed to submit to Saad's judgment, the Messenger of Allah ﷺ sent for him. He was nearby, so he came riding a donkey. When he drew near, the Prophet ﷺ said, "Stand up for your master."
لما نزلت بنو قريظة على حكم سعد، بعث رسول الله ﷺ إليه، وكان قريبا، فجاء على حمار، فلما دنا قال النبي ﷺ: قوموا إلى سيدكم.
Bukhari narrated it in the Book of Jihad and Expeditions (3043), and Muslim in the Book of Jihad (1768), both from the hadith of Shubah, from Saad bin Ibrahim, from Abu Umama, who is the son of Sahl bin Hunayf, from Abu Saeed Khudri, and he mentioned it.