Don't be afraid to sacrifice everything, and everyone, and even your very lives for Christ | PadreCast: Twentieth Sunday Ordinary Time

The key is the whole phrase: He did not come to bring peace on earth. Christ's kingdom as He Himself has said, is "not of this world." Peace reigns in His kingdom, that is, heaven. Not here. And people that are willing to do anything to maintain peace in this world oftentimes go quickly to hell, because they seek peace at any cost. Even the cost of truth, goodness, beauty. ...

This is the most basic mistake all of us make in trying to discern the right thing. We make decisions based on hypotheticals. You don't know the future. All you can know is what your actions mean.