“Blessed are the peacemakers, for they shall be called sons of God.” applies only to those who are worthy:
Matthew 10:12–15 (ESV): »As you enter the house, greet it. And if the house is worthy, let your peace come upon it, but if it is not worthy, let your peace return to you. And if anyone will not receive you or listen to your words, shake off the dust from your feet when you leave that house or town. Truly, I say to you, it will be more bearable on the day of judgment for the land of Sodom and Gomorrah than for that town.«