The Heartbeat of the Old Testament

One of the unfortunate characterizations of the Bible is that the Old Testament is primarily about law and external commandments, while the New Testament is about grace and one’s heart. An honest Bible student need look no further than the book of Deuteronomy to see the fallacy in this thinking. Deuteronomy uses the Hebrew word for “heart” at least 47 times, earning it the appropriate description as “the heartbeat of the Old Testament.” Deuteronomy illustrates, perhaps better than any book of the Bible, the combination of heart, soul, mind, and body in our service to God. God wants us to give Him everything we have. Notice a few things Deuteronomy says about our hearts.

Our heart is where we choose to love God as the sole object of our worship (Deut. 6:4-6). It is where we seek God and His will (Deut. 4:29), fear Him (Deut. 5:29), and remember that there is no God like Him (Deut. 4:39). It is from a reverential and humble heart that we obey His commandments (Deut. 10:12-13).

Deuteronomy also warns that we must guard our hearts as our most vital spiritual organ. With our hearts we can forget God and His powerful deeds done on our behalf (Deut. 4:9). Our hearts can be deceived by idolatry as we turn away from God (Deut. 11:16), and they can become proud and hardened by prosperity (Deut. 8:11-14) or self-righteousness (Deut. 9:4). The fear of God can be replaced by a fear of mankind and military might (Deut. 7:17-19). Our hearts can become “uncircumcised” (an Old Testament metaphor for unclean or impure) and stubborn if we are not careful (Deut. 10:16). Each of these dangers remind us to “watch over your heart with all diligence, for from it flows the springs of life” (Prov. 4:23).

It should come as no surprise that God often tests our hearts. When God led His people through the wilderness 40 years, allowing them to experience hunger and thirst (while never letting them die of starvation) He was testing them, “to know what was in [their] heart, whether [they] would keep His commandments or not” (Deut. 8:2). Also, the rise of false prophets would test how deeply they loved God in their hearts (Deut. 13:3). Are we to think that God no longer tests us similarly today? Anytime we are faced with life’s difficulties or the allure of false teaching, it is an opportunity to sharpen our devotion to God and every word that proceeds out of His mouth (Deut. 8:3). “Search me, oh God, and know my heart,” the Psalmist prayed (Ps. 139:23).

Furthermore, Deuteronomy teaches us that God cares about our attitude in every detail of life. While emphasizing the heart, Moses also repeated some of the specific laws unique to the covenant between God and Israel. This marriage of “law and love” shows that God’s law (even under the Old Covenant) is never arbitrary but intended to teach us principles about how to love Him. While those specific laws are made obsolete by the blood of Christ (Heb. 8-9), the principles behind the laws are made timeless by God’s never-changing nature.

For instance, Deuteronomy 15:7-11 commanded the Israelites to generously care for the poor among them. Yet the act of giving alone is not enough, for God warned against a heart that makes excuses for not assisting the needy (v. 9) or that grieves and regrets when we do help others (v. 10). Not only does God care about our actions, but He wants those actions to have proper motives behind them.

Every living person has a heart. Whether consciously or unconsciously, every person loves something as the object of their deepest desire and affection. Therefore, no man is excused when he seeks after money, possessions, power, popularity, acceptance, or any other idol before God. Also, the true condition of our hearts may be hidden from others, but never from God. We cannot use “you can’t judge my heart” as an excuse to sin, for God knows and will judge every thought and intent of our hearts (Heb. 4:12). It matters not how our hearts stand before other people, only how they stand before God. How does yours?

When Moses had finished speaking all these words to all Israel, he said to them, “Take to your heart all the words with which I am warning you today, which you shall command your sons to observe carefully, even all the words of this law. For it is not an idle word for you; indeed, it is your life” (Deut. 32:45-47).