ירמיהו, פרק י״ז, פסוק י׳

Divine justice relies on a profound understanding of human nature, penetrating the hidden layers of the mind and soul far beyond what is visible on the surface. Only God possesses the ability to reach the very bottom of these inner thoughts [ביאור שטיינזלץ]. Because He clearly sees a person's true intentions, no one can hide behind false excuses or claim that their wrongdoings lacked full intent [צאינה וראינה].

God examines the internal human process on two distinct levels, actively searching and thoroughly testing the individual [מצודת ציון]. To grasp a person's true essence, He evaluates both the kidneys and the heart [מצודת דוד]. The kidneys function as the internal advisors that generate the initial spark of an idea, while the heart serves as the ultimate decision-maker that resolves to carry out the action [רד״ק]. Emphasizing both of these internal centers highlights the absolute thoroughness of God's evaluation [מצודת דוד].

The ultimate purpose of this deep internal investigation is to deliver proper justice [ביאור שטיינזלץ]. God not only searches the mind but also holds the active power to give every individual the exact outcome they deserve [רד״ק]. When evaluating an individual, He considers both the broad, general path they have chosen in life and the specific details of their everyday actions [רד״ק]. Ultimately, God repays people based on the actual fruits of their behavior [מצודת ציון], which are the practical, real-world results of their internal thoughts and choices [מצודת דוד]. Because this evaluation reaches the very core of human motivation, the resulting justice is guaranteed to be absolutely precise and completely free of error [צאינה וראינה].