Blessed are the peacemakers: for they shall be called the children of God. The simplest way to explain this is someone who makes peace. Helping others to get along would be a big part of it. The second part of this beatitude says: then you will be called the children of God. Being God's child would mean that you truly are a part of God's family and that you're starting to be more like Him; just like we are with our parents.