Shaykh Zayd al-Madkhali (rahimahullaah) stated:
The one who is truly a companion is the one who aids his brother according to that which he (the one reminding) is able to do, even if it is with the statement of good. He aids him by way of giving (his brother) the (beneficial) advice (even if that advice goes) against him. When he forgets anything, he reminds him in order that he (i.e. the one reminding) establishes the rights of companionship. (This is) especially in that which is connected to the matters of the religion. He reminds him, advises him and does good to him. All of that is from fulfilling the rights of companionship. As for the one who doesn’t remind you when you forget, and he doesn’t aid you when you are in need of him, (then) indeed he has not established the rights of companionship. That’s because he doesn’t know its status and the status of that which comes as a result of fulfilling (rights of companionship) with the companions (that he have).