Full Idea
If God's divine influence stopped, every operation would stop. Every operation, therefore, of everything is traced back to him as cause.
Gist of Idea
Without God's influence every operation would stop, so God causes everything
Source
Thomas Aquinas (Summa Contra Gentiles [1268], III.67), quoted by Brian Davies - Introduction to the Philosophy of Religion 3 'Freedom'
Book Reference
Davies,Brian: 'An Introduction to the Philosophy of Religion' [OUP 1993], p.42
A Reaction
If the systematic interraction of mind and body counts as an 'operation', then this seems to imply Occasionalism.