Blessed are the peacemakers: for they shall be called the children of God.
What exactly is a peacemaker? It is a someone who seeks peace and does what is needed to obtain and/or keep peace. In many places in the Bible, God calls us to seek peace or live in peace.
1 Corinthians 7:15b says,
but God hath called us to peace.
When we follow God's commands, we show we are His children; therefore, we need to seek peace.