“If (the Pope) lays down an order contrary to right customs one does not have to obey him; if he tries to do something manifestly opposed to justice and to the common good, it would be licit to resist him; if he attacks by force, he could be repelled by force, with the moderation characteristic of a good defence.” - Suarez, De Fide, disp.X sect.6, n.16.
 
“If a man is sincerely convinced that what his superior commands is displeasing to God, he is bound not to obey…The word ‘superior’ certainly includes the Pope.”  - Cardinal Newman, Difficulties of Anglicans, pp.260-61.

“If the Faith be in danger, prelates ought to be accused by their subjects, even in public. Thus, St. Paul, who was the subject of St Peter, called him to task in public because of the impending danger of scandal concerning a point of Faith. As the gloss of St Augustine says on Gal 2:11: ‘St Peter himself set an example for those who rule, to the effect that if they ever stray from the right path they are not to feel that anyone is unworthy of correcting them, even if such a person be one of their subjects.’” - St Thomas Aquinas, S.Th.IIaIIae,q33a4ad2.
 
"Although it clearly follows from the circuмstances that the Pope can err at times, and command things which must not be done, that we are not simply to be obedient to him in all things, that does not show that he must be obeyed by all when his commands are good. To know in what cases he is to be obeyed and what not, it is said in the Acts of the Apostles: 'One ought to obey God rather than man'; therefore, were the Pope to command anything against Holy Scripture, or the articles of the Faith, or the truths of the Sacraments, or the commands of the natural or the divine law, he ought not to be obeyed, but in such commands, to be passed over, ignored." - Cardinal Torquemada OP (1388-1468), Summa de Ecclesia, p47-48

"Great as our filial duty of reverence is towards whatever (the Pope) may say, great as our duty of obedience must be to the guidance of the Chief Shepherd, we do not hold that every word of his is infallible, or that he must always be right" - Raphael Cardinal Merry del Val, The Truth of Papal Claims, 1902,  p19...  Commenting on St Paul's resisting St Peter as related in Galatians: "Even today a bishop might expostulate with a Pope, who in his judgement might be acting in a way which was liable to mislead those under his own charge, and then write to his critics that he had not hesitated to pass strictures upon the action of the successor of St Peter... The hypothesis is quite conceivable and in no way destroys or diminishes the supremacy of the Pope. And yet an individual bishop does not occupy the exceptional position of St Paul, a fellow Apostle of the Prince of the Apostles. Even a humble nun, St Catherine of Siena, expostulated with the reigning Pontiff in her day, whilst fully acknowledging all his great prerogatives." -Card Merry del Val, Ibid. p74

“Were he (the Pope) to wish to destroy the Church or to commit an act of similar magnitude, there would be a duty to prevent him, and likewise an obligation to oppose him and resist him. The reason being that he does not possess power in order to destroy, and thus it follows that if he is doing so it is lawful to oppose him” - Sylvester Prieras, prominent Dominican defender of papal authority against Martin Luther, in Dialogus de Potestate Papae, 1517.

“If the Pope by his orders and his acts destroys the Church, one can resist him and impede the execution of his commands.” - Vitoria, Dominican theologian, Obras de Francisco de Vitoria pp. 486-67                                                                                                                                                                                                                                                                                                               
“Just as it is licit to resist the Pontiff who attacks the body, so also is it licit to resist him who attacks the souls or destroys the civil order, or above all destroys the Church. I say that it is licit to resist him by not doing what he orders and by impeding the execution of his will…” - St Robert Bellarmine, De Summo Pontifice, n.30, lib.II, cap.102 

Matthew 23

1 Then Jesus spoke to the multitudes and to his disciples,  2 Saying: The scribes and the Pharisees have sitten on the chair of Moses.  3 All things therefore whatsoever they shall say to you, observe and do: but according to their works do ye not; for they say, and do not.

Ver. 2. The Scribes. They, who professed the greatest zeal for the law of Moses, and gloried in being the interpreters of it, sat upon the chair of Moses, succeeded to his authority of governing the people of God, of instructing them in his law, and of disclosing to them his will. Such, therefore, as did not depart from the letter of the law, were called Scribes. But such as professed something higher, and separated themselves from the crowd, as better than the ordinary class of men, were called Pharisees, which signifies, separated. Origen. — God preserveth the truth of the Christian religion in the apostolic See of Rome, which in the new law answers to the chair of Moses, notwithstanding the disedifying conduct of some few of its bishops. Yes, though a traitor, as vile as Judas himself, were a bishop thereof, it would not be prejudicial to the integrity of the faith of God's Church, or to the ready obedience and perfect submission of sincere good Christians, for whom our Lord has made this provision, when he says: do that which they say, but do not as they do. S. Aug. Ep. clxv.


Ver. 3. All therefore whatsoever they shall say. S. Augustine, in his defence of the Apostolic See, thus argues, contra lit. Petil. "Why dost thou call the apostolic chair the chair of pestilence? If, for the men that sit therein, I ask: did our Lord Jesus Christ, on account of the Pharisees, reflect upon the chair, wherein they sat? Did he not commend that chair of Moses, and, preserving the honour of the chair, reprove them? For he sayeth: they have sat on the chair of Moses. All therefore whatsoever they shall say to you, observe and do. These points if you did well consider, you would not, for the men whom you defame, blaspheme the Apostolic See, wherewith you do not hold communion." l. ii. c. 51. And again, c. 61. Ibid. "Neither on account of the Pharisees, to whom you maliciously compare us, did our Lord command the chair of Moses to be forsaken; (in which chair he verily figured his own) for he warned the people to do what they say, and not what they do, and that the holiness of the chair be in no case forsaken, nor the unity of the flock divided, on account of the wicked lives of the pastors." — Christ does not tell them to observe every thing, without exception, that the Pharisees should say to them; for, (as it was observed in a previous chapter) many superstitions and false ordinances had obtained amongst them, corrupting the Scriptures by their traditions; but only such as were not contrary to the law of Moses. We are taught to obey bad no less than good ministers, in those things that are not expressly contrary to the law of God. Hence appears how unfounded and unreasonable is the excuse so often adduced by persons in justification of their misdeeds, viz. that they saw their pastors do the same. Such must attend to the rule here given by Jesus Christ. What they say, do: but according to their works, do ye not. Dion. Carthus. — The words, all whatsoever, shew that nothing must be excepted, but what the supreme law orders to be excepted. E.

Saying, &c. By seat we here understand the honour, dignity, and authority of teaching and commanding, which Moses had with the Jєωs, and to which the Scribes had succeeded. We gather from S. Luke iv. 16, that the Scribes not only sat, but sometimes stood when they taught. In like manner, the chair of S. Peter is used to signify the power and authority of teaching and ruling all the faithful throughout the world, in which the Roman Pontiffs succeed S. Peter. For otherwise no Pontiff ever sits now in that actual wooden chair in which S. Peter sat, but it is religiously preserved in his basilica, and is shown to the people every year on the Feast of S. Peter’s Chair, to be venerated. Hence S. Jerome said to Damasus, “I am united in communion to your blessedness, that is, to the chair of Peter.” For although as a private man the Pontiff may err, yet when he defines anything ex cathedra, that is, by his Pontifical authority concerning the faith, he cannot err, because he is assisted by the Holy Ghost.


Observe, many of the Scribes and Pharisees were priests or Levites, whose duty it was to teach the people (Mal. ii. 7). But Christ did not wish to name the Priests, because He would not derogate from the sacerdotal honour.


All things therefore whatsoever, &c. He means, of course, all things not contrary to Moses and the Law. For the doctrine of the Scribes, when they taught men to say corban to their parents, was contrary to the Law, as Christ showed (xv. 4). In like manner, it was contrary to the Law of Moses to teach, as the Scribes did, that Jesus was not the Messiah, or the Christ. For Jesus showed those very signs and miracles which Moses and the Prophets had foretold Messiah would perform. In such things, therefore, the people must not follow the doctrine of the Scribes, nor be obedient to them; but in other things, in which their teaching was generally conformable to the Law of Moses, it was their duty to obey them. Christ therefore here teaches that all the other dogmas of the Scribes, which were not repugnant to the law, even though they were vain and foolish, and therefore not binding (for that a law should be obligatory, it must command something honest and useful, as Civilians and Theologians teach in their treatises upon laws, also D. Thomas, 1. 2 quæst. 95, art. 3), such as were the frequent washings of the hands and other parts of the body, might yet serve for the merit of blind and simple obedience, and for reverence of the sacerdotal order. So Jansen, Franc. Lucas, and others. But Maldonatus restricts the word all to such commands alone as are contained in the Law of Moses. Certainly these were what Christ chiefly referred to.

OT is not NT.

Pope Pius IX defined the scope of obedience for you so you don't have to extrapolate anything yourself, just submit to the clear teaching of the Pope, the universal and supreme Teacher.

Romans 15:4

For what things soever were written, were written for our learning: that through patience and the comfort of the scriptures, we might have hope.

I'll say this, though you won't listen - after all, it's only OT.

The same power or charism given to the pope was given to the High Priest under the Old Covenant:

22. And surely what these sons of perdition intend is quite clear from their other writings, especially that impious and most imprudent one which has only recently been published by the person whom they recently constituted as a pseudo-bishop. For these writings attack and pervert the true power of jurisdiction of the Roman Pontiff and the bishops, who are the successors of blessed Peter and the apostles; they transfer it instead to the people, or, as they say, to the community. They obstinately reject and oppose the infallible magisterium both of the Roman Pontiff and of the whole Church in teaching matters. Incredibly, they boldly affirm that the Roman Pontiff and all the bishops, the priests and the people conjoined with him in the unity of faith and communion fell into heresy when they approved and professed the definitions of the Ecuмenical Vatican Council. Therefore they deny also the indefectibility of the Church and blasphemously declare that it has perished throughout the world and that its visible Head and the bishops have erred. They assert the necessity of restoring a legitimate episcopacy in the person of their pseudo-bishop, who has entered not by the gate but from elsewhere like a thief or robber and calls the damnation of Christ upon his head. 

Reminds me of the absurdity at the 1988 consecrations. "Habetis Mandatum Apostolicuм?" Schmidberger: "Habemus."

A flat out lie. Not only did they not have an apostolic mandate, they had an explicit prohibition.

But even if it was, what would be your point? That you're free to ignore and reject your Pope's teaching? Pius IX clearly told you you have to obey everything, from Roman congregations to discipline.

If tonight someone holds a gun to my head, demanding me to sign Dignitatis Humanae, God give me strength to die a martyr!

If the gunman demands I sign Vatican II as a whole, I will only do so after having made clear that by virtue of the Explanatory Note, I accept nothing in the texts that contradicts Tradition.

I will never volunteer to sign my name under the council.

If I become pope, within 3 minutes the entire council will be Number One on the newly revived Index of Forbidden Books.

This was the attitude of Archbishop Lefebvre.