Shama-il Tirmidhi Chapter 035, Hadith Number 005 (229).

Anas ibn Malik radiyallahu anhu reports, A resident of the wilderness whose name was Zaahir (ibn Hiraam Al-Ashjaee), whenever he visited Rasooluallah sallallahu alaihe wasallam he brought with him presents of the wilderness, vegetables etc., and presented it to Rasoolullah sallallahu alaihe wasallam. When he intended to leave Madinah, Rasoolullah sallallahu alaihe wasallam used to present him with provisions of the city. Once Rasoolullah sallallahu alaihe wasallam said, Zaahir is our wilderness, and we are his city. Rasoolullah sallallahu alaihe wasallam was attached to him. Zaahir radiyallahu anhu was not very handsome. Rasoolullah sallallahu alaihe wasallam once approached him while he was selling his merchandise. Rasoolullah sallallahu alaihe wasallam caught him in between the arms from the back in such a manner that he (Sayyidina Zaahir radiyallahu anhu) could not see him. Zaahir radiyallahu anhu said, Who is this?, leave me. But when he saw with the corner of his eye that it was Rasoolullah sallallahu alaihe wasallam, he straightened his back and began pressing it to the chest of Rasoolullah sallallahu alaihe wasallam (For as long as he gained this opportunity it was better than a thousand gifts). Rasoolullah sallallahu alaihe wasallam then said, Who will purchase this slave? Zaahir radiyallahu anhu replied, O Rasool of Allah, if you shall sell me, you will be selling a defective thing, and will earn a very little sum. Rasoolullah sallallahu alaihe wasallam said, No, you are not defective in the sight of Allah, but very valuable.

Commentary
Sayyidina Rasoolullah sallallahu alaihe wasallam coming and embracing him from the back and covering the eyes of Sayyidina Zaahir radiyallahu anhu was being humorous to him. This saying that who shall purchase him was also in joking. Because Sayyidina Zaahir radiyallahu anhu was not a slave but a free man. Some of the commentators have written that this hadith is about joking, but in reality it is full of virtues and hidden benefits. When Sayyidina Rasoolullah sallallahu alaihe wasallam found him engrossed in selling his merchandise. Sayyidina Rasoolullah sallallahu alaihe wasallam feared that because he was too busy selling, it would keep him away from the remembrance of Allah. Therefore Sayyidina Rasoolullah sallallahu alaihe wasallam took hold of him from behind, and the embrace would be a means of returning him to the remembrance of Allah. As a reminder he said, Is there anyone who will purchase this slave?, it is because the person who is so engrossed in things other than the remembrance of Allah, is like a slave of his own desires. The embrace of Rasoolullah sallallahu alaihe wasallam totally awakened his faculties for the remembrance of Allah. This is why Sayyidina Rasoolullah sallallahu alaihe wasallam gave him the good news that his status in the eyes of Allah is not low but that of an elevated one.