Hawzah News Agency – The merciful prophet of Islam (pbuh) says:

مَن باعَ واشْتَرى‏ فلْيَجْتَنِبْ ‏خَمسَ خِصالٍ، وإلّا فلا يَبيعَنَّ ولا يَشْتَرِيَنَّ: الرِّبا، والحَلْفَ، وكِتْمانَ العَيبِ، والحمدَ إذا باعَ، والذَّمَّ إذا اشْتَرى‏.

'Whoever sells or buys must avoid five habits, or he should not sell or buy at all: usury, [false] oaths, hiding the defects [of merchandise], praising what he sells, and showing disapproval for what he intends to buy.'

Source: Bihar al-Anwar, v. 103, p. 95, no. 18