The Prophet of Allah, sallallaahu ‘alayhi wa sallam, mingled with them in their markets, and would order them to do good and forbid them from doing evil
Rifaa`ah (a Companion) said
“We went with the Messenger of Allah, sallallaahu ‘alayhi wa sallam, and found the people selling early in the morning, and
then he called them, saying: ‘O merchants.’ When they looked up and stretched
their necks, he, sallallaahu ‘alayhi wa sallam, said: ‘Merchants are resurrected as sinners, except those who fear Allah, fulfill their oaths, and are honest.’”
Al-Mubaarakpoori (a scholar) said: “The term, “Except those who fear Allah,” meaning, by avoiding major sins, as well as minor sins, such as cheating and deceitfulness. It also includes being good to people when trading with them, or doing acts of obedience to Allah and worshipping Him.
Al-Qaadhi (a scholar) said: “This narration occurred because usually, the practice of merchants in dealing with others involves hiding facts (about the merchandise) when dealing. They also strive to put their merchandise in circulation through any possible means, such as lying while swearing, and so forth. So the Prophet of Allah, sallallaahu ‘alayhi wa sallam, ruled these actions as being actions of sinfulness, and gave the exception to those who keep away from forbidden practices, fulfill their oaths, and are honest when speaking.”