Is it obligatory for the Imam to appoint judges in other cities?

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The Imam, if residing in a specific city, must send judges (Qudah) to other administrative centers (Amsar) outside his own city. This duty is established by the practice of the Prophet, peace be upon him, who sent Ali and Mu'adh ibn Jabal as judges to Yemen. Furthermore, Umar appointed Shuayh as judge for Kufa and Ka'b ibn Suwar for Basra, and instructed Abu Ubaydah and Mu'adh to appoint judges in Sham. The necessity arises because the inhabitants of every city require a judge, and traveling to the Imam's city is difficult for them, thus obligating the provision of local judicial authority.