A man related that once I saw two men negotiating a sale of a goat and the buyer was urging the merchant to be lenient in the price. Then I saw a man coming who was very handsome, with beautiful features and a thin nose and delicate eyebrows, wearing old cloaks. When he neared he greeted us and we answered and then the man who was buying the goat called him and said 'O Rasool of Allah! Tell the man here to make a lenient trade with me' He, raising his hand replying, 'You people are free over your property and wealth, I am mindful that I go on the Day of Judgement in this state that I have none of you who has any claims upon me and I am not guilty of oppressing or compelling anyone- whether it be regarding blood, honour or wealth. Whatever I do, it should be the for the sake of Allah. And Allah shows mercy to he who is clement in his dealings of buying and selling, gentle in paying his debts and gentle in collecting his debts.
(haithami v 9 pg 18, as quoted in Hayatus Sahabah of Maulana Yusuf Kandhlawi)
This beautiful story just spells out for us the extent of the struggle that the Messenger of Allah went through to convey the deen to us without getting an ounce of worldly benefit for himself.