INMATES OF NEW BILIBID PRISON v. DOJ G.R. No. 212719, June 25, 2019 PERALTA, J.: TOPICS: WHAT IS A PENAL LAW? RETROACTIVE EFFECT OF PENAL LAWS FACTS: Then President Benigno Aquino III signed into law R.A. No. 10592 amending Articles 29, 94, 97, 98, and 99 of the Revised Penal Code. An IRR was jointly issued by DOJ and DILG. Petitioners and intervenors assails the validity of its Section 4, Rule 1 that directs the prospective application of the grant of good conduct time allowance, time allowance for study, teaching and mentoring, and special time allowance for loyalty mainly on the ground that it violates Article 22 of the Revised Penal Code. ISSUE: What is a penal law? Should R.A. No. 10592 should be given retroactive effect? HELD: The Supreme Court defined penal law as, "those acts of the Legislature which prohibit certain acts and establish penalties for their violation; or those ...