Tenn. Code § 17-323
The chief justice of the Supreme Court of Tennessee is empowered to assign judges who are now retired or who may be retired hereafter, (1) to hold any court in the state whenever in his judgment it is necessary to do so in order to relieve congested dockets, or (2) to sit for judges who may be incapacitated or who may be absent because of illness or otherwise. A retired judge holding court hereunder shall be paid, in addition to his retirement benefits for the period during which he sits as judge, the difference between his retirement benefits for the period and the amount he would receive for that period if he were an active judge of the same court. The chief justice shall certify to the judicial cost accountant in the office of the comptroller of the treasury the date on which such service commences and the date on which such service terminates.
Provided however, the chief justice of the Supreme Court of Tennessee shall likewise be empowered to assign and designate any attorney-general as defined under § 8-618 who has or may be retired as such attorney-general to sit as judge and hold any court in the same manner, for the same purpose and he shall have the same authority, duty and jurisdiction as any retired judge is now authorized to perform or exercise under the provisions of this section.
Provided further, when the retired attorney-general is designated and assigned hereunder by the chief justice to sit as judge, his jurisdiction shall be limited and restricted to habeas corpus cases and such cases as may arise under any post-conviction procedure act.
Provided further, the retired attorney-general assigned and designated to sit and perform the duties and functions of a judge shall have served at least twenty-four (24) years as such attorney-general prior to his retirement. His compensation hereunder shall include his regular retirement benefit as attorney-general, plus the difference between his retirement benefit and the amount he would receive if he were an active or regular judge of the same court. The chief justice shall certify to the executive secretary of the Supreme Court the date on which such service commences, and the date on which such service terminates.
T.C.A. § 17-323