A transgression–that is, a disruption of the order in the system–has two results.
First, it causes a kind of short circuit and skews or distorts the descent of divine plenty.
Second, the shock set off by this short circuit stimulates the world of the kelipot, the outer shells, and causes them in turn to set off a negative charge within the particular system that belongs to the life of the transgressor.
This is what is meant by the reward and punishment that are said to follow on every action of a human being.
Nor is it only a deed that so affects the system of the Sefirot.
It is also a thought, an intention, or any of the various stirrings of the human soul.
–Rabbi Adin Steinsaltz