QUESTION:What does it mean that God searches “the reins and hearts” (Rev. 2:23, KJV)?
The Bible associates certain emotional and psychological experiences with body organs. This is not totally foreign to the way we also use the language of emotions. In the English-speaking world the heart is the seat of emotions. We tell our spouses, “I love you with all my heart.” Obviously the reference is not to the physical organ inside our chests. We mean that our love comes from the very depth of our being, and is, therefore, genuine. In the Bible this practice is much more common. I will deal only with the usage of the term “kidneys” (“reins”).
1. A Physical Organ: The Israelites knew about the physical organ known as the kidneys. The kidneys of the sacrificial animals were burnt on the altar of sacrifices, probably because they were usually covered with fat (Ex. 29:13; Lev. 3:4), and the Israelites had been for-bidden to consume the fat of animals. The Jewish thinker Philo of Alexandria (c. 20 B.C- A.D. 45), appears to suggest that the kidneys were offered to God because they purified the blood (Special Laws 1:216). In Babylonian divinatory rituals the kidneys of some animals were used to predict the future. Thus, burning them on the altar was, for the Israelites, a rejection of such pagan practices. Like many other parts of the body, kidneys were used to designate the whole person (a part of the body represented the totality of the body or person). The psalmist writes, “You created my inmost being [kelāyôth, ‘kidneys’]” (139:13),* meaning “my body.” Since the kidneys were located in the innermost part of the human body, it was easy to use them metaphorically to designate the innermost aspects of human personality.
2. Seat of Emotions: The Israelites understood that emotions could not be separated from the physical body. The father tells his son, “My inmost being [kidneys] will rejoice when your lips speak what is right” (Prov. 23:16). In this case, the literal translation was avoided in English in order to indicate that the term “kidneys” is being used metaphorically to indicate that joy is deep and possesses the whole person. Negative emotions were also associated with the kidneys. When the psalmist wrote “my spirit [was] embittered” (Ps. 73:21), he was literally saying, “my kidneys were pierced,” meaning that he was emotionally disturbed and in profound distress. The image is that of a person who has been pierced by an arrow to the kidneys and is in pain, fearing death, emotionally agonizing. In fact, Job describes his emotional distress by using the image of archers shooting arrows at him and piercing his kidneys (16:12, 13; cf. Lam. 3:13). His innermost being was emotionally upset.
3. Seat of Character: According to Jeremiah the people of Israel constantly spoke about God with their lips, but He was “far from their hearts [kidneys]” (12:2), that is to say, God’s message had not transformed their inner being. Here the kidneys are associated with character. In cases like this they become a synonym for the biblical term “heart,” which represents, among other things, the rational, moral qualities of a person. They symbolically refer to human self-awareness or the innermost mind. It could, then, designate the conscience. The psalmist may have had this in mind when he wrote, “Even at night my heart [kidneys] instructs me” (16:7).
4. Object of Divine Analysis: Since the kidneys are associated with character development, it is easy to conclude that God examines them. The phrase you quoted—God searches “the reins and the heart”—is used several times in the Old Testament. It assumes that God sees the innermost being of humans and can make righteous decisions based on that knowledge (Jer. 11:20; 17:10). The psalmist has nothing to hide, so he says to the Lord, “Test me, O Lord, and try me, examine my heart [kidneys] and my mind [lēb, ‘heart’]” (26:2). By examining the kidneys God can identify the wicked and bring to an end their violence (Ps. 7:9). The combination of kidneys and heart in the phrase indicates that God examines the totality of the person.
The use of human organs to refer to human emotions reveals that biblical writers had a wholistic understanding of human nature. The physical body was not detached from the spiritual and emotional sides of the person.
*Unless otherwise noted, all Scripture quotations in this article are from the New International Version.