230.Do not envy one another; do not inflate prices one to another; do not hate one another; do not turn away from one another; and do not undercut one another, but be you. O servants of Allah, brothers. A Muslim is the brother of a Muslim: he neither oppresses him nor does he fail him, he neither lies to him nor does he hold him in contempt. Piety is right here-and the Prophet (peace be upon him) pointed to his breast three times. It is evil enough for a man to hold his brother Muslim in contempt. The whole of a Muslim for another is inviolable: his blood, his property and his honour.
(Muslim).
(Forty Hadith translated by. Ezzedin Ibrahim and Denys Johnson-Davies).