There should be no harm or reciprocal harm. Whoever causes harm, Allah harms him, and whoever makes things difficult, Allah makes things difficult for him

The Prophet (may Allah's peace and blessings be upon him) pointed out that we should avert harm from ourselves and others in all its kinds and manifestations. It is equally impermissible for anyone to harm himself or harm others. It is also not permissible to respond to harm with harm, for harm will not be removed with harm, except by way of legal retribution, without transgression.

Then, the Prophet (may Allah's peace and blessings be upon him) warned that whoever harms people will be harmed, and whoever makes things hard for people will find hardship.