I'm not spiritual. Peter says, you don't start with being qualified. You start with the God of all grace. Grace precedes qualification. You may have this promise freely, if you will believe in this God of all grace.
Dominion means superior strength.
God has dominion over the devil. He is stronger than Satan. Therefore when he promises to successfully get us through the jungle of this world and bring us to glory, he can do it and will do it. Dominion belongs to the Lord. He is a God of all grace.