Question: The Torah says that 70 souls descended into Egypt, although we know that there were tens of thousands of people. Why are we talking about this particular number?
Answer: To start with, there really were not many people in the time of Abraham. The Torah always refers not to the number of people, but to the power of souls.
“70” is a complete number because our soul consists of 70 parts. If these 70 parts are connecting together and aim their personal and common efforts to Keter, to the peak of connection, then this is called “complete work,” “the whole soul,” i.e., the connection with the Creator by combining these qualities.
From KabTV’s “Spiritual States” 6/11/21