Salman Farsi (RA) was a governor of Medinah. Once he was walking by a market place. Due to the simplicity of his clothing, a person thought that he must be a poor man and asked him to carry his materials in exchange of some money. Salman (RA) picked up the materials and didn't reveal his identity. As they were walking, the people of Medinah were shocked. "Oh Allah have mercy on Ameer-ul-Mo'mineen (leader of the faithful). Let us carry the materials." they said. But Salman (RA) denied all their requests and carried on with the man. Upon realizing who Salman (RA) was, the man who told him to carry the stuff felt embarrassed and kept asking him for forgiveness. Salman (RA) told him "Don't worry! Let's keep going." He took the materials all the way to the man's home. After this incident, that man promised to himself that he will never ask somebody to carry his materials again. Source: Tambihul Ghafileen, by Faqih Abul Layth Smarkandi (RA).