St. Catherine in Papal Court
Even if the Pope were Satan incarnate, we ought not to raise up our heads against him, but calmly lie down to rest on his bosom. He who rebels against our Father is condemned to death, for that which we do to him we do to Christ: we honor Christ if we honor the Pope; we dishonor Christ if we dishonor the Pope. I know very well that many defend themselves by boasting: “They are so corrupt, and work all manner of evil!” But God has commanded that, even if the priests, the pastors, and Christ-on-earth were incarnate devils, we be obedient and subject to them, not for their sakes, but for the sake of God, and out of obedience to Him. - Saint Catherine of Siena in St. Catherine of Siena, SCS, p. 201-202, p. 222.
h/t Fr. Z