God introduces itself to Moses, telling Moses God’s real name the one we are not allowed to pronounce, the name that we avoid by saying Adonai.
Until now, says God to Moses, your ancestors called me God, moving forward you can use my personal name, the real one.
Knowing someone and calling them by their first name is very different than calling them by their title. It is more intimate and more personal.
God has moved closer in the relationship between God and Israel. Through Moses, we know God and relate to God more intimately.