“I once said to abu ‘Abd Allah (a.s.), that I buy food in a deal in the beginning of which I lose and in the end I gain profit. I then ask my friend to reduce a certain amount on each kur. He (the Imam) said, ‘There is nothing good in it, however, he can reduce a certain sum.’ I then asked, ‘Can he reduce more than I have lost?’ He (the Imam) said, ‘It is not harmful.’ I then asked if I can keep aside one or two kur and the man asks me to give him according to my measurement. He (the Imam) said, ‘It is not harmful if he can trust you.’”