1987 Constitution of the Philippines
Section 13. The conclusions of the Supreme Court in any case submitted to it for the decision en banc or in division shall be reached in consultation before the case the case assigned to a Member for the writing of the opinion of the Court. A certification to this effect signed by the Chief Justice shall be issued and a copy thereof attached to the record of the case and served upon the parties. Any Member who took no part, or dissented, or abstained from a decision or resolution must state the reason therefor. The same requirements shall be observed by all lower collegiate court.