Adam Clarke on Genesis 31:32

Let him not live - It appears that anciently theft was punished by death; and we know that the patriarchs had the power of life and death in their hands. But previously to the law, the punishment of death was scarcely ever inflicted but for murder. The rabbins consider that this was an imprecation used by Jacob, as if he had said, Let God take away the life of the person who has stolen them! And that this was answered shortly after in the death of Rachel, Gen 35:16-19.