Brethren: Rejoice in the Lord always; again, I say, rejoice. Let your modesty be known to all men. The Lord is nigh. Be nothing solicitous; but in every thing, by prayer and supplication, with thanksgiving, let your petitions be made known to God. And the peace of God, which surpasseth all understanding, keep your hearts and minds in Christ Jesus. For the rest, brethren, whatsoever things are true, whatsoever modest, whatsoever just, whatsoever holy, whatsoever lovely, whatsoever of good fame, if there be any virtue, if any praise of discipline, think on these things. The things which you have both learned, and received, and heard, and seen in me, these do ye, and the God of peace shall be with you.
Verse 6. But in every thing by prayer, &c. By the Greek, the sense and construction cannot be in every prayer; but in every thing, in all circumstances, have recourse to prayer. Wi.
Verse 8. For the rest, brethren, whatsoever things are true, &c. Here the apostle enumerates general precepts of morality, which they ought to practise. — Whatsoever things are true. In words, in promises, in lawful oaths, &c. he commands rectitude of mind and sincerity of heart. — Whatsoever things are modest. By these words he prescribes gravity in manners, modesty in dress, and decency in conversation. — Whatsoever things are just. That is, in dealing with others, in buying or selling, in trade or business, to be fair and honest. — Whatsoever things are holy. By these words may be understood, that those who are in a religious state professed, or in holy orders, should lead a life of sanctity and chastity, according to the vows they make; but these words being also applied to those in the world, indicate the virtuous life they are bound by the divine commandments to follow. — Whatsoever things are amiable. That is to practise those good offices in society that procure us the esteem and good will of our neighbours. — Whatsoever things are of good repute. That is, that by our conduct and behaviour we should edify our neighbours, and give them good example by our actions. — If there be any virtue, if there be any praise of discipline: that those in error, by seeing the morality and good discipline of the true religion, may be converted. And finally, the apostle commands not only the Philippians, but all Christians, to think on these things: that is, to make it their study and concern, that the peace of God might be with them. Ch.
From the Encyclical "Mirari vos arbitramur," Aug. 15, 1832
Having embraced with paternal affection those especially who have applied their mind particularly to the sacred disciplines and to philosophic questions, encourage and support them so that they may not, by relying on the powers of their own talents alone, imprudently go astray from the path of truth into the way of the impious. Let them remember “that God is the guide of wisdom and the director of the wise” [cf. Wisd. 7:15], and that it is not possible to learn to know God without God, who by means of the Word teaches men to know God. It is characteristic of the proud, or rather of the foolish man to test the mysteries of faith “which surpasseth all understanding” [Phil. 4:7] by human standards, and to entrust them to the reasoning of our mind, which by reason of the condition of our human nature is weak and infirm.