Pope Benedict XVI on the Papacy
“In fact, the First Vatican Council had in no way defined the pope as an absolute monarch. On the contrary, it presents him as the guarantor of obedience to the revealed Word. The pope’s authority is bound to the Tradition of faith [.] … The authority of the pope is not unlimited; it is at the service of Sacred Tradition.”
Joseph Cardinal Ratzinger (now Pope Benedict XVI), The Spirit of the Liturgy (Ignatius Press: San Francisco, 2000, page 166).