Strangely enough, despite his hesitancy around her, Countess Lydia pays Karenin a call. Countess Lydia goes straight to Karenin's study and finds him in the depths of despair over this weird split between his moment of forgiveness for Anna and the painful social consequences of his actions.
She says lots of rote spiritual things about accepting "He Who Dwells in Karenin's Heart," adding that Karenin's forgiveness of Anna arose from Christ.
Countess Lydia offers (uninvited) to run Karenin's household, but everything she does is wrong. Secretly, the one who winds up doing all of the work is Karenin's valet Kornei, who pragmatically becomes the real organizer of all of Karenin's household stuff.
Countess Lydia's first act as the supposed manager of Karenin's life is to find Seryozha and inform him that his father is a saint and his mother, Anna, is dead.
Countess Lydia's presence helps Karenin by distracting him from his despair and giving him moral support. At the same time, she talks constantly about religion, converting Karenin to a "new kind" of Christianity popular in Petersburg, which promises salvation to its followers.
In his heart, Karenin feels that this brand of religion is much less powerful than his personal epiphany about forgiveness for Vronsky and Anna. But he embraces it anyway, because it makes him feel superior to the unsaved (even if he doesn't really believe in the kind of salvation this type of Christianity offers).