Today's OF gospel is from Matthew 10:37ff. But the omitted preceding verses are important to understand the cause of the dissension: false peace!
Saint Thomas' commentary on verse 34 ("I have come to bring a sword, not peace") distinguishes between two types of peace: good and bad. The name peace means concord. There is a bad peace (i.e. bad agreements among men). Wisdom 14:22 In Evangelium Matthaei, Caput X.
That is a passage about men serving either their affections or their kings to give up true worship for false worship, which resulted in total social disorder, all agreed upon by men! The parallel's with our democratic age are serious: killing the babies and confusing marriage and sexual morality, all agreed upon by men "in a great war of ignorance," such great evils, which they call "peace" and "independence."
Wisdom 14:22-26
And it was not enough for them to err about the knowledge of God, but whereas they lived in a great war of ignorance, they call so many and so great evils peace.
For either they sacrifice their own children, or use hidden sacrifices, or keep watches full of madness,
So that now they neither keep life, nor marriage undefiled, but one killeth another through envy, or grieveth him by adultery:
And all things are mingled together, blood, murder, theft and dissimulation, corruption and unfaithfulness, tumults and perjury, disquieting of the good,
Forgetfulness of God, defiling of souls, changing of nature, disorder in marriage, and the irregularity of adultery and uncleanness.