Jurisdiction is to a Court what a door is to a house. The question of a Courts jurisdiction is called a threshold issue because it is at the threshold of the temple of justice. Jurisdiction is a radical and fundamental question of competence, for if the Court has no jurisdiction to hear the case, the proceedings are and remain a nullity, however well conducted and brilliantly decided they might have been. A defect in competence is not intrinsic but rather extrinsic to adjudication. Oloba v. Akereja (1988)3 NWLR (Pt.84)508; Oloriode v. Oyebi (1984) 1 SCNLR 390; Ezomo v. Oyakhire (1985) 1 NWLR (Pt. 2) 105; Petrojessica Ent. Ltd. v. Leventis Technical Co. Ltd. (1992) 5 NWLR (Pt. 244) 675; Barclays Bank v. C.B.N. (1976) 6 SC 175; African Newspapers (Nig.) Ltd. v. F.R.N. (1985) 2 NWLR (Pt. 1006) 608; A.-G., Anambra State V. A.-G., Fed. (1993) 6 NWLR (Pt. 302) 692; Saleh v. Monguno (2003) 1 NWLR (Pt. 801) 221. (The underlining is supplied by us for emphasis). Under the Nigerian legal system, Courts are creations or creatures of statutes or legislations such as the grundnorm itself, that is, the Constitution or Decrees or Acts or Laws or Edicts. Hence, it is the legislations themselves that cloak the Courts with powers or adjudicatory jurisdiction. Therefore, if the Constitution, Decrees, Acts, Laws and Edicts do not grant jurisdiction to a Court, the Court itself and or parties cannot by agreement endow the Court with jurisdiction. For once there is a defect in the competence of a Court to adjudicate upon an action, the proceedings in the action no matter how otherwise so well, properly and brilliantly conducted would amount to a nullity and an exercise in futility. Therefore, since Courts are creatures of statutes, their jurisdiction is confined, limited, restricted and circumscribed by the statutes creating them. Moreover, a Court must study the statute which creates it and must not misconstrue same to exercise jurisdiction not donated to it thereby. See also the cases of: (1) Ndaeyo v. Ogunnaya (1977) 1 SC p. 11; (2) National Bank of Nigeria v. Shoyoye (1977) 5 SC p. 181 and (3) A.-G., Fed. v. Guardian Newspapers Ltd. (1999) 9 NWLR (Pt. 618) p. 187.
— O.F. Omoleye JCA. Amaechi V. The Governor of Rivers State & Ors. (CA/PH/342/2015, 8 May 2017)