The poor in spirit are of the heavenly aspect being children of God. The meek are of the earthly aspect trusting in God like a child. So they are the Light of the World bringing the heavenly to Earth.
The merciful are of the heavenly aspect imitating God the Father in their prudence. The peacemakers are of the earthly aspect imitating Jesus in justice. They are called children of God as they are the Light of the World.
