“I once asked abu Ja‘far (a.s.), about the case of advance payment for meat. He (the Imam) said, ‘You must not go close to it because one time he gives you fatty, one time what is about to become spoilled and one time he gives you boney. Buy with examination and in hand in hand manner.’ I then asked about advance payment for containers of water. He (the Imam) said, ‘You must not go close to it because one time he gives you less and one time complete. Buy it with examination; it is safe for you and for him.’”