Answer
The principle of abuse of rights, in Article 19 of the Civil Code, requires every person, in the exercise of his rights and in the performance of his duties, to act with justice, give everyone his due, and observe honesty and good faith. A person who exercises even a legal right in a manner that violates this standard may be held liable in damages. In Globe Mackay Cable and Radio Corp. v. Court of Appeals (G.R. No. 81262), the Supreme Court fixed the elements of an abuse of rights: (1) the existence of a legal right or duty, (2) which is exercised in bad faith, and (3) for the sole intent of prejudicing or injuring another.
Good faith is presumed, so the person claiming an abuse of rights carries the burden of proving the bad faith and the intent to injure. Article 19 sets the standard, but the award of damages is usually anchored on it together with Article 20 (for acts contrary to law) or Article 21 (for acts contrary to morals, good customs, or public policy).