Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: I used to trade camels in Baqi‘. Sometimes I would sell them for dinars and receive dirhams instead, and sometimes I would sell them for dirhams and receive dinars instead. This one would take in place of that, and that one would be given in place of this. Once I presented myself before the Prophet (peace and blessings of Allah be upon him), and he was at that time in the house of Lady Hafsa. I said:“O Messenger of Allah! I want to ask you a question. I trade camels in Baqi‘, and sometimes I sell them for dinars but receive dirhams, and sometimes I sell them for dirhams and receive dinars. I take this in place of that, and that in place of this.”The Prophet (peace and blessings of Allah be upon him) said:“There is no harm in this, as long as you take according to the rate of that day, as long as you both do not separate or no condition is set between you.”In another narration, there is some variation in the wording.