Why is God called by different names in different ages? What are the significances of God’s names?

Relevant Words of God:

You should know that God originally had no name. He only took on one, or two, or many names because He had work to do and had to manage mankind. Whatever name He is called by, isn’t it freely chosen by Him? Does He need you, a creature, to decide it? The name by which God is called is according to what man can apprehend and the language of man, but this name cannot be encapsulated by man.