Honor Thy Family

The quest is obtained when the player character disrespects the Dark Brotherhood and is thus banished from engaging in their activities.

Becoming banished
There are several known ways to be banished by the Dark Brotherhood:
 * Feeding on contract kills (with the Ring of Namira equipped).
 * Stealing, killing, and/or feeding on a Dark Brotherhood member.
 * Note that the Spectral Assassin and Shadowmere count as members.
 * Killing the Dark Brotherhood's tame pet Frostbite Spider, Lis.

Becoming readmitted
After being banished from the Dark Brotherhood, the player character will not be able to perform any contracts until he talks to Nazir. If the player has a Dark Brotherhood Initiate as a follower, he will refuse to speak to him and will stop following him until the player is re-admitted.

The player may also speak to Nazir and he will ask for a payment fine of 500 gold (the amount diminishes if the player possess high speech skills and/or perks). Paying Nazir will complete the quest and the player will be re-admitted into the Brotherhood.

Unlike in, the Dragonborn can rejoin the Dark Brotherhood as many times as he/she likes.

One strange part about this is that during the quest The Cure For Madness, killing Cicero may trigger the quest Honor Thy Family, even though Cicero has betrayed the Dark Brotherhood himself and such it is unknown why Nazir and the others would care about the Dragonborn attacking him.

Journal entries
Семейная честь