1987 Constitution of the Philippines
Section 14. No Senator or Member of the House of Representatives may personally appear as counsel before any court of justice or before the Electoral Tribunals, or quasi-judicial and other administrative bodies. Neither shall he, directly or indirectly, be interested financially in any contract with, or in any franchise or special privilege granted by the Government, or any subdivision, agency, or instrumentality thereof, including any government-owned or controlled corporation, or its subsidiary, during his term of office. He shall not intervene in any matter before any office of the Government for his pecuniary benefit or where he may be called upon to act on account of his office.