63 Clearly no sincere Catholic can refuse to accept the formulation of Christian doctrine more recently elaborated and proclaimed as dogmas by the Church, under the inspiration and guidance of the Holy Spirit with abundant fruit for souls, because it pleases him to hark back to the old formulas. No more can any Catholic in his right senses repudiate existing legislation of the Church to revert to prescriptions based on the earliest sources of canon law. Just as obviously unwise and mistaken is the zeal of one who in matters liturgical would go back to the rites and usage of antiquity, discarding the new patterns introduced by disposition of divine Providence to meet the changes of circumstances and situation.
Source: Mediator Dei (Vatican.va)