To justify their bad behavior with their parents, some people say: they don’t treat us well, so we behave with them the way they do. We must say to this people that respecting the parents is a moral and religious duty and it is not conditioned on their good behavior toward us. If they do something wrong, you are not allowed to retaliate. Their mistake must not justify your wrong behavior and misconduct. If their behavior was excellent and flawless and you also respected them, you have not done something extraordinary. If you respect them while they behave wrongly with you, then you have really done something extraordinary and respected them.
source : erfan.ir