דברי הימים א, פרק י״ט, פסוק ה׳

The aftermath of a diplomatic mission gone wrong left King David's ambassadors in a state of severe public humiliation. Word quickly reached the king detailing the incident and the degraded condition in which his men were returning [מצודת דוד, ביאור שטיינזלץ]. The ambassadors felt a deep, lingering shame as they were forced to travel all the way from the land of Ammon back to their own country bearing such a disgraceful appearance [ביאור שטיינזלץ].

Because of this overwhelming embarrassment, the men could not bring themselves to appear before the king. Recognizing their distress, David took the initiative and sent representatives out to meet them on the road [מצודת דוד]. He informed the ambassadors that they were not required to present themselves before him in their current state [ביאור שטיינזלץ]. Instead, he instructed them to remain quietly in the city of Jericho and wait until their beards fully grew back [מצודת ציון]. Only after their appearance was restored were they to continue the journey back to their own homes [מצודת דוד].