The Messenger of Allah ﷺ used to sit among his companions, so when a stranger came, he could not tell which of them was the Prophet until he asked. We requested the Messenger of Allah ﷺ to allow us to make a seat for him by which the stranger would recognize him whenever he came.So we built him a bench of clay, and he sat upon it while we sat on either side of him.He then mentioned the rest of the report, saying that a man approached, and he described his appearance, until he gave the greeting from the edge of the gathering and said, "Peace be upon you, Muhammad."The Prophet ﷺ returned the greeting to him.
حدثنا عثمان بن أبي شيبة حدثنا جرير عن أبي فروة الهمداني عن أبي زرعة بن عمرو بن جرير
كان رسول الله ﷺ يجلس بين ظهري أصحابه فيجيء الغريب فلا يدري أيهم هو حتى يسأل فطلبنا إلى رسول الله ﷺ أن نجعل له مجلسا يعرفه الغريب إذا أتاه قال فبنينا له دكانا من طين فجلس عليه وكنا نجلس بجنبتيه وذكر نحو هذا الخبر فأقبل رجل فذكر هيئته حتى سلم من طرف السماط فقال السلام عليك يا محمد قال فرد عليه النبي ﷺ
[Its isnad is sahih] Nasai narrated it in the Book of Faith, Chapter on the Description of Faith and Islam, no. 4994, from the hadith of Jareer bin Abdul-Hameed with this wording, and its basic version is found in Muslim, no. 9.