Before our universe there was another (spiritual;) this is called the world of Tohu.
Two souls from that universe came to repair our world (for that world was filled with love, humility etc.) the first is Chanoich – he came before the flood (if not for his soul teaching humanity, the world would have suffered total destruction) and then came Moshe.
The greatness of our universe is the ten sefiros (the three intellect and seven emotions) interact, creating new benefits.
In our universe, each part has something contributory (the head can think, the feet can take the head places, the heart feels, and it’s all interconnected.)
Moshe who came from the higher world (where the lights are unique and not interconnected) was humbled by seeing the benefit of our souls/universe.
Moshe believed His light (from the higher universe) was too great to descend (as he said, “my mouth cannot speak”) but God said: “I created both the light and the vehicles” (of expression) and therefore, I can merge the two.