4. No person shall be liable to be tried or punished in any court in Nigeria for an offence,
except under the express provisions of the code or of some Act or Law which is in force in, or forms part of the law of Nigeria :
Provided that in the case of an offence committed before the commencement of this Act the
offender may be tried and punished either under the law in force when the offence was committed or under the code, provided that the offender shall not be punished to any greater extent than was authorised by the former law.

Part 1
Introductory
Interpretation: Application: General Principles

Chapter 3
Application of Criminal Law

11. A person shall not be punished for doing or omitting to do an act of unless the act or omission constituted an offence under the law in force when it occurred.

Article 11
Jurisdiction ratione temporis
2. If a State becomes a Party to this Statute after its entry into force, the Court may exercise its jurisdiction only with respect to crimes committed after the entry into force of this Statute for that State, unless that State has made a declaration under article 12, paragraph 3.

Article 24
Non-retroactivity ratione personae
1. No person shall be criminally responsible under this Statute for conduct prior to the entry into force of the Statute.
2. In the event of a change in the law applicable to a given case prior to a final judgement, the law more favourable to the person being investigated, prosecuted or convicted shall apply.