"I used to sell gold for silver, or silver for gold. I came to the Messenger of Allah and told him about that, and he said: 'If you make a deal with your companion, d o not leave him when there is still any ambiguity (in the deal) between you."' (Using translation from Nasāʾī 4583)
كُنْتُ أَبِيعُ الذَّهَبَ بِالْفِضَّةِ وَالْفِضَّةَ بِالذَّهَبِ فَأَتَيْتُ رَسُولَ اللهِ ﷺ فَأَخْبَرْتُهُ بِذَلِكَ فَقَالَ «إِذَا بَايَعْتَ صَاحِبَكَ فَلَا تُفَارِقْهُ وَبَيْنَكَ وَبَيْنَهُ لَبْسٌ»