When is it permissible for a Muslim to abandon his Muslim brother for more than three days?

It is forbidden to abandon a Muslim for more than three nights, except for a legitimate reason, such as innovation in beliefs, open declaration of sins, or fear of harm to the abandoning person's religion or self. The Prophet, peace and blessings be upon him, abandoned those who lagged behind from the Battle of Tabuk. It is permissible to abandon a disobedient wife in bed after admonition. Abandonment is a remedy that should only be resorted to if it is highly probable that it will yield a greater benefit than reconciliation.