“kidneys...heart.” The “kidneys” refers to a person’s emotional life. The Word of God points to the fact that our kidneys, bowels, and belly (or womb) are part of our mental/emotional life, not “just physical organs.” Our “gut,” including our intestines, bowels, kidneys and stomach contain as many nerve cells as our brain, and studies are now showing that our “gut” contributes significantly to our emotional life and health. In contrast, in the biblical world, the “heart” refers to the thoughts, not the emotions. When the Bible mentions “heart” and “kidneys” together, it refers to the thought life (“heart”) and emotional life (“kidneys”). [For more on the heart referring to the thought life, see commentary on Prov. 15:21. For more on kidneys referring to the emotional life, see commentary on Rev. 2:23, “kidneys”].
“cause.” The Hebrew word is riyb (#7378 רִיב), and it means to quarrel or contend, to lodge a complaint, to make a lawsuit against. Here Jeremiah commits his cause (his legal case) to God.