It is a well-known doctrine that a judge should detach himself from cases where his decision is appealed to a higher court for review. The raison d’etre for such doctrine is the fact that a judge is not an active combatant in such proceeding and must leave the opposing parties to contend their individual positions and the appellate court to decide the issues without his active participation. When a judge actively participates in the appeal of his judgment, he, in a way, ceases to be judicial and has become adversarial instead.[26]
http://sc.judiciary.gov.ph/jurisprudence/2007/november2007/169982.htm
Batas Pinoy 