Jabir bin Abdullah (may Allah be pleased with them both) says that he sold a camel to the Prophet (peace and blessings of Allah be upon him) on the way and made it a condition that he would ride it to his family. 1

Imam Tirmidhi says:
1- This hadith is Hasan Sahih.
2- This is also narrated from Jabir through other chains.
3- Some of the Companions and others among the people of knowledge act upon this. They consider a condition in a sale to be permissible when there is only one condition. This is also the view of Ahmad and Ishaq bin Rahwayh.
4- And some of the people of knowledge say that a condition in a sale is not permissible, and when there is a condition in it, the sale is not complete.

Jabir bin Abdullah narrated: "I married a woman and went to the Prophet, he said: 'O Jabir! Have you married?' I said: 'Yes.' He said: 'A virgin or a matron?' I said: 'A matron.' He said: 'Why didn't you marry a young girl, so that you may play with her and she with you?' I said: 'O Messenger of Allah! Abdullah (his father) died and left behind seven - or nine - daughter, so I have brought someone who can look after them.'" (He said:) "So he supplicated for me."