The Brainliest Answer!
In this proverb the "hand" is being referred to that of a mother, who usually rocks the cradle of her child.
By "rules the world" it would mean that the mother, who raises the child is shaping the personality of the child or shaping the personality of a generation.
So most probably the proverb means that mothers shapes the personality of a generation or the  society that the generations will make.
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