The phrase
"tyrannical power" refers to an oppressive or cruel form of authority, in which someone or a group has absolute control, often using it to harm or control others without considering their rights or freedoms.
Full definition
The simple pages of Genesis reveal in sheer majesty both the original plan of God, and the qualities of human nature in that beginning, and what could, and did befall if man ate of the tree of the experience of sin: the harmony with God is destroyed, and
the tyrannical power of the soul in man, if man adores himself as his sole centre of life and meaning, is to bring into the flesh a storm of unruly desire and addictive greed.