Appointment of Chief Judge and Judges of the High Court of the Federal Capital Territory, Abuja
Section 256(3) · 1999 Constitution (2004 edition)
What Constitution says
(3) A person shall not be qualified to hold the office of a Chief Judge or a Judge of the High Court of the Federation Capital Territory, Abuja unless he is qualified to practice as a legal practitioner in Nigeria and has been so qualified for a period of not less than ten years.
This is the 1999 Constitution as published in 2004. Later amendments aren't included yet, so a section may have changed since.
Original source
Official Gazette · CFRN 1999 official PDF · printed page 110. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections