What is your rule of Faith concerning these times?

Pope Leo XIII, Sapientiae Christianae:

It happens far otherwise with Christians; they receive their rule of faith from the Church, by whose authority and under whose guidance they are conscious that they have beyond question attained to truth...

To determine, however, which are the doctrines divinely revealed belongs to the teaching Church, to whom God has entrusted the safekeeping and interpretation of His utterances. But the supreme teacher in the Church is the Roman Pontiff. Union of minds, therefore, requires, together with a perfect accord in the one faith, complete submission and obedience of will to the Church and to the Roman Pontiff, as to God Himself. This obedience should, however, be perfect, because it is enjoined by faith itself, and has this in common with faith, that it cannot be given in shreds; nay, were it not absolute and perfect in every particular, it might wear the name of obedience, but its essence would disappear…

“The faith of the whole Church should be one, according to the precept (1 Cor. 1:10): “Let all speak the same thing, and let there be no schisms among you”; and this cannot be observed save on condition that questions which arise touching faith should be determined by him who presides over the whole Church, whose sentence must consequently be accepted without wavering. And hence to the sole authority of the supreme Pontiff does it pertain to publish a new revision of the symbol, as also to decree all other matters that concern the universal Church.”
In defining the limits of the obedience owed to the pastors of souls, but most of all to the authority of the Roman Pontiff, it must not be supposed that it is only to be yielded in relation to dogmas of which the obstinate denial cannot be disjoined from the crime of heresy. Nay, further, it is not enough sincerely and firmly to assent to doctrines which, though not defined by any solemn pronouncement of the Church, are by her proposed to belief, as divinely revealed, in her common and universal teaching, and which the [First] Vatican Council declared are to be believed “with Catholic and divine faith.” But this likewise must be reckoned amongst the duties of Christians, that they allow themselves to be ruled and directed by the authority and leadership of bishops, and, above all, of the Apostolic See.

Wherefore it belongs to the Pope to judge authoritatively what things the sacred oracles contain, as well as what doctrines are in harmony, and what in disagreement, with them; and also, for the same reason, to show forth what things are to be accepted as right, and what to be rejected as worthless; what it is necessary to do and what to avoid doing, in order to attain eternal salvation. For, otherwise, there would be no sure interpreter of the commands of God, nor would there be any safe guide showing man the way he should live.