Physiologically, the heart is an organ in the body, and in the Bible it is also used in a number of metaphors. The NT uses the Greek term kardia similarly to the OT Hebrew terms leb and lebab and in some cases depends on OT usage.

Mind and Emotions

Metaphorically, the heart refers to the mind, the will, the seat of emotions, or even the whole person. It also refers to the center of something or its inner part. These metaphors come from the heart’s importance and location.

Mind. The heart refers to the mind, but not the brain, and in these cases does not involve human physiology. It is a metaphor, and while the neurophysiology of the heart may be interesting in its own right, it has no bearing on this use of language. We also should not confuse some modern English idioms or distinctions as being related to the biblical viewpoint. The Bible does not make a distinction between “head knowledge” and “heart knowledge,” nor does it employ language making the “heart” good or superior and the “head/mind” bad, inferior, or merely intellectual. It does not prize the emotional over the thoughtful; it has a more integrated viewpoint.

Deuteronomy 6:5 issues the command to love God with all one’s heart, soul, and strength. When the command is repeated in the Gospels, it occurs in three variations (Matt. 22:37; Mark 12:30; Luke 10:27). Common to all three is the addition of the word “mind.” The Gospel writers want to be sure that the audience hears Jesus adding “mind,” but this addition is based on the fact that the meaning of the Hebrew word for “heart” includes the mind.

The mental activities of the metaphorical heart are abundant. The heart is where a person thinks (Gen. 6:5; Deut. 7:17; 1 Chron. 29:18; Rev. 18:7), where a person comprehends and has understanding (1 Kings 3:9; Job 17:4; Ps. 49:3; Prov. 14:13; Matt. 13:15). The heart makes plans and has intentions (Gen. 6:5; 8:21; Prov. 20:5; 1 Chron. 29:18; Jer. 23:20). One believes with the heart (Luke 24:25; Acts 8:37; Rom. 10:9). The heart is the site of wisdom, discernment, and skill (Exod. 35:34; 36:2; 1 Kings 3:9; 10:24). The heart is the place of memory (Deut. 4:9; Ps. 119:11). The heart plays the role of conscience (2 Sam. 24:10; 1 John 3:20–21).

It is often worth the effort to substitute “mind” for “heart” when reading the Bible in order to grasp the mental dimension. For example, after telling the Israelites to love God with all their heart, Moses says, “These commandments that I give you today are to be upon your hearts” (Deut. 6:6). Reading it instead as “be on your mind” changes our perspective, and in this case the idiom “on your mind” is clearer and more accurate. The following verses instruct parents to talk to their children throughout the day about God’s words. In order for parents to do this, God’s requirements and deeds need to be constantly on their minds, out of their love for him. Similarly, love for God and loyalty are expressed by meditation on and determination to obey his law (Ps. 119:11, 112). The law is not merely a list of rules; it is also a repository of a worldview in which the Lord is the only God. To live consistently with this truth requires careful, reflective thought.

Emotions and attitude. The heart, as the seat of emotion, is associated with a number of feelings and sentiments, such as gladness (Exod. 4:14; Acts 2:26), hatred (Lev. 19:17), pride (Deut. 8:14), resentment (Deut. 15:10), dread (Deut. 28:67), sympathy (Judg. 5:9), love (Judg. 16:15), sadness (1 Sam. 1:8; John 16:6), and jealousy and ambition (James 3:14). The heart is also the frame of reference for attitudes such as willingness, courage, and desire.

Idioms

The word “heart” also appears in several idioms.

Hardness of heart. A hard heart is obstinate or averse (Mark 3:5), while a tender heart is humble (2 Kings 22:19). In the book of Exodus the translations typically say that God or Pharaoh hardened Pharaoh’s/his heart. These passages in Exodus use not the Hebrew words for hardness but rather those for being heavy or for strengthening. The neutral sense of strengthening the heart takes on nuances in context for being bold or obstinate. Pharaoh was strengthened in his opposition to God, and this obstinacy fits the idiom of having a hard heart.

Uncircumcised/circumcised heart. An uncircumcised heart is a metaphor for an obstinate and rebellious heart, while a circumcised heart is linked to being humble and faithful (Lev. 26:41; Deut. 30:6; Jer. 4:4; Acts 7:51). Perhaps the metaphor is based on the role of circumcision in the covenant.

“A man after his [God’s] own heart” (1 Sam. 13:14). This description of David may mean either “according to his [God’s] choice” (cf. 2 Sam. 7:21), stressing God’s choice over the people’s choice, or it may mean “in accordance with his [God’s] desire” (1 Sam. 14:7; 1 Kings 15:3), referring to how David showed conformity with God’s agenda.

All the heart. The phrase “with all [one’s] heart” in some cases means “wholeheartedly” or “single-mindedly,” which emphasizes unity of purpose and focus. In other cases it seems to mean, more broadly, “with all of one’s thinking or perspective” and implies the work of adjusting our worldview away from common cultural assumptions and toward God’s teaching.

Say in one’s heart. This expression denotes talking to oneself (i.e., thinking) rather than out loud or indicates reflection or deliberation. There are several warnings not to lie to oneself—that is, not to deliberate, believe, and act on the stated false premise.

Take [a matter] to heart. To take something to heart is to take it very seriously or to give it high priority.

A person exempted from military training and service on the basis of deeply held religious convictions against participating in warfare.

Jesus’ call to “not resist an evil person” and to “turn to them the other cheek” (Matt. 5:39; Luke 6:29–36) makes the clearest case for Christian conscientious objection. Jesus also blessed peacemakers (Matt. 5:9), commanded love of enemy and neighbor (Matt. 5:44; 22:39; Mark 12:31), and refused to build his kingdom by force (John 6:15; 18:36). Beyond violence, war may violate the Christian’s conscience because it often necessitates deception and breeds fear, hatred, greed, and pride, be it individual, national, ethnic, or otherwise.

Conversely, Christians are obligated to obey civil authorities (Rom. 13:1–6; Titus 3:1; 1 Pet. 2:13–14), for whom Scripture reserves the right to wield the sword (Rom. 13:4). Some argue that these verses allow or oblige believers to fight when called to duty. Furthermore, this sinful world may require loving one’s neighbors by using violence to protect them. If Christians enjoy the freedoms and well-being defended by a military, should they not contribute to it in combat, provided the war is just?

If Jesus condemns violence, however, the conscientious objector may invoke Peter’s claim, “We must obey God rather than human beings!” (Acts 5:29; cf. 4:19). Many nonviolent forms of resistance exist, so conscientious objectors may still help defend their country by serving in the military or elsewhere in noncombatant roles.

A feeling of animosity, a disposition toward hostility, rejection, or negative favoritism.

Hate is as old as the conflict between Cain and Abel or as the rebellion of Satan. Many stories involve hatred and animosity between people (e.g., Gen. 37:4; 2 Sam. 13:22). Beside humans hating each other, people hate God and that which is morally upright (Exod. 20:5; Deut. 5:9; 7:10; 32:41; Pss. 68:1; 81:15; 120:6). It is correct, however, to hate sin (Pss. 97:10; 101:3; Prov. 8:13), as God does (Ps. 5:6; Prov. 6:16–19; Isa. 61:8; Rev. 2:6), though he takes no pleasure in the death of the wicked (Ezek. 18:23; 33:11). The two great commandments oppose the tendency to hate by calling us to love God wholly and love our neighbor as ourselves (Lev. 19:18; Deut. 6:5; 10:12; Matt. 22:37; Mark 12:33; Luke 10:27). The reverse is also commanded: we should not hate our neighbor (Lev. 19:17) nor even hate our enemy, but rather do good and pray for our enemy (Exod. 23:4–5; Prov. 25:21; Matt. 5:44; Luke 6:27; cf. Deut. 10:19). Hateful actions are not necessarily motivated by hateful feelings, as a father who does not give needed punishment to his son is said to treat him with hatred (Prov. 13:24).

With regard to a hate crime, the main issue was intent—that is, whether an accident had occurred or whether a murder had been committed deliberately, “with malice aforethought” (Num. 35:20). Hate was a criterion of intent and had to be established by multiple witnesses for the two parties involved. Having hate did not garner greater punishment or make it a worse crime; hatred signified that it was a crime because it was intentional (Deut. 4:42; 19:4, 6, 11; Josh. 20:5).

With regard to marriage, in a polygamous marriage there was a danger of preferential treatment: a loved wife and a hated wife. The law forbids reducing the care of one wife in favor of another (Exod. 21:10) and protects the rights of the firstborn son even if he is born to the hated wife (Deut. 21:15–17). Hatred may be expressed by either party withholding conjugal relations. This probably lies behind the description in Gen. 29:31 of Jacob hating Leah (some translations say “unloved”).

Rejection, favoritism, or preference may be called “hate,” as in the case of a nonpreferred wife in a polygamous marriage, in not choosing Esau to continue the covenant line (Mal. 1:2–3; Rom. 9:13), or in not having a greater love for Christ than anything else (Matt. 6:24; Luke 14:26; John 12:25).

A feeling of animosity, a disposition toward hostility, rejection, or negative favoritism.

Hate is as old as the conflict between Cain and Abel or as the rebellion of Satan. Many stories involve hatred and animosity between people (e.g., Gen. 37:4; 2 Sam. 13:22). Beside humans hating each other, people hate God and that which is morally upright (Exod. 20:5; Deut. 5:9; 7:10; 32:41; Pss. 68:1; 81:15; 120:6). It is correct, however, to hate sin (Pss. 97:10; 101:3; Prov. 8:13), as God does (Ps. 5:6; Prov. 6:16–19; Isa. 61:8; Rev. 2:6), though he takes no pleasure in the death of the wicked (Ezek. 18:23; 33:11). The two great commandments oppose the tendency to hate by calling us to love God wholly and love our neighbor as ourselves (Lev. 19:18; Deut. 6:5; 10:12; Matt. 22:37; Mark 12:33; Luke 10:27). The reverse is also commanded: we should not hate our neighbor (Lev. 19:17) nor even hate our enemy, but rather do good and pray for our enemy (Exod. 23:4–5; Prov. 25:21; Matt. 5:44; Luke 6:27; cf. Deut. 10:19). Hateful actions are not necessarily motivated by hateful feelings, as a father who does not give needed punishment to his son is said to treat him with hatred (Prov. 13:24).

With regard to a hate crime, the main issue was intent—that is, whether an accident had occurred or whether a murder had been committed deliberately, “with malice aforethought” (Num. 35:20). Hate was a criterion of intent and had to be established by multiple witnesses for the two parties involved. Having hate did not garner greater punishment or make it a worse crime; hatred signified that it was a crime because it was intentional (Deut. 4:42; 19:4, 6, 11; Josh. 20:5).

With regard to marriage, in a polygamous marriage there was a danger of preferential treatment: a loved wife and a hated wife. The law forbids reducing the care of one wife in favor of another (Exod. 21:10) and protects the rights of the firstborn son even if he is born to the hated wife (Deut. 21:15–17). Hatred may be expressed by either party withholding conjugal relations. This probably lies behind the description in Gen. 29:31 of Jacob hating Leah (some translations say “unloved”).

Rejection, favoritism, or preference may be called “hate,” as in the case of a nonpreferred wife in a polygamous marriage, in not choosing Esau to continue the covenant line (Mal. 1:2–3; Rom. 9:13), or in not having a greater love for Christ than anything else (Matt. 6:24; Luke 14:26; John 12:25).

Shema is the transliteration of a Hebrew word meaning “hear” (shema’ ), the first word of Deut. 6:4: “Hear, O Israel: The Lord our God, the Lord is one.” The text that begins with this verse is therefore referred to as the Shema. The Shema emphasizes the oneness of God and the obligation to love him and is the most important prayer in Judaism. It is recited twice daily and begins a weekly liturgical reading that includes Deut. 6:4–9; 11:13–21; Num. 15:37–41. These Torah passages emphasize monotheism and the centrality of the commandments.

Jesus called the Shema the greatest commandment (Mark 12:29–30; Matt. 22:37–38; Luke 10:27) and invoked it in teaching his oneness with the Father (John 10:30). Paul later expanded the Shema to include Jesus (1 Cor. 8:6).