The elementary rule of pleading is that a party shall plead facts which he propose to rely upon in order to establish his own case. It is now trite law that a party will not be allowed to lead evidence in respect of facts not pleaded; or to lead evidence contrary to his pleading. The sole purpose of pleading is to ensure that the parties to the case know the case they will meet at the trial, to obviate element of surprise. Pleading saves time and brings out clearly the issues in the case.
— Olatawura JSC. African Continental Bank Ltd. v. Alhaji Umaru Gwagwada (SC.26/1990, 29 APR 1994)