They would talk to him in the same way as they talked to other people, paying no attention to his position as God’s messenger. His companions who were close to him recognized his very refined manners and spoke to him with the respect due to him. Therefore, when a Bedouin was rough with the Prophet, his companions would be greatly displeased. Yet the Prophet always defused the situation in the best way.
Abu Hurayrah reports that “a man claimed the repayment of a debt owed to him by the Prophet and spoke to him in an ill-mannered way. The Prophet’s companions were about to stop him, but God’s messenger said: ‘Leave him. A person with a rightful claim has his say.’ He then told them to give the man a camel of the same age as his. They came back to tell him that they could only find better camels. The Prophet said: ‘Give him one. Among the best of you are those who repay their debts best.’” (Related by Al-Bukhari).
The Prophet had borrowed a camel from this Bedouin at a time of scarcity. The Prophet needed the camel for the poor who were deserving beneficiaries of zakat. The Prophet wanted to slaughter the camel to feed them, or to sell it and buy provisions for them. He promised the Bedouin to repay him with a camel like his own. When people brought the Prophet their zakat and there were some camels as part of that, the man came over and demanded repayment in a very rough manner that shocked the Prophet’s companions. They were about to silence the man, as he had no need to speak in that manner to the Prophet. The Prophet had not delayed payment, and the man had not made a demand before. So, why should he not observe good manners? However, the Prophet stopped them and told them that the man had a right, and that gave him a strong position.
The Prophet then ordered that the man should be given a camel of the same age as the one he borrowed from him. There was none. The available camels were all better than his, either they were younger if his was too old, or they were older if his was very young. The Prophet told them to give him a better camel.
The question that arises here is whether this constitutes usury, as Islam is very strict in the prohibition of usury. The answer is that it does, but only if this was agreed between the two parties at the time when the transaction took place, or later but before the repayment. There was no such agreement between the Prophet and the Bedouin. We realize this from the fact that the Prophet made clear in his instructions that he should be given a camel of the same age as the one he borrowed. Moreover, the Bedouin, whose name we do not know, did not ask for a better one. He only asked to be repaid. The Prophet’s subsequent instructions meant that the man would take a better camel which would fetch a higher price than his own. Yet this was the Prophet’s own decision, made out of his own free will. In this case, no element of usury is involved. The increased value was a gift given by the Prophet to the Bedouin as a gesture of appreciation of his original help.
In short, if one borrows something from a relative, friend or stranger and at the time of repayment he gives a better value, out of his own choice, and without any pressure or implied request by the lender, this is perfectly permissible. In fact it is a kindness which God rewards as He pleases.