We are accustomed to say that God created the world out of nothing. That doctrine has its value, but it belongs more to philosophy or theology than to the Bible's way of speaking. The account in Genesis, even though it may not actually use the word "harmony" emphasises in different ways that God's work of creation was a work of harmony. The notion of harmony, of the beauty of order, is a significant part of the worldview of Genesis.
Vatican Council II teaches us that by divine wisdom and grace that God chose to reveal himself to us. It is not too much to suggest that it was in divine wisdom and grace also that God created the world in harmony. All of creation is replete with the wisdom of divine love, the harmony of divine love.
Proverbs is one of the wisdom books of the Old Testament. In speaking of various details and aspects of social harmony in the world, the author is also teaching that the promotion of this harmonious well-being in society is the fruit of the divine wisdom which God has shared with us in creation and in revelation.
Lord in Your wise and loving providence, guide us that we may wisely work for a more harmonious and humane society.