He is the one ruler of many who (seem to act, but really do) not act; he makes the one seed manifold. The wise who perceive him within their self, to them belongs eternal happiness, not to others.

In plain words: God is the one ruler behind many things that seem to act on their own but really do not. He turns one seed into many things. Wise people who find him within themselves have lasting happiness, and no one else does.