Ubida b. al-Simit (Allah be pleased with him) reported Allah's Messenger ﷺ as saying: Gold is to be paid for by gold, silver by silver, wheat by wheat, barley by barley, dates by dates, and salt by salt, like for like and equal for equal, payment being made hand to hand. If these classes differ, then sell as you wish if payment is made hand to hand.
The Prophet Muhammad ﷺ also taught us about being generous when making payments; if there is a difference between two classes of goods then one can make payment as desired as long as it is done hand to hand. This encourages people to be fair and generous when dealing with others in business transactions or exchanges of goods and services.
