By David Powlison 2007
from Chapter on “I Am Motivated When I Feel Desire” in “Seeing With New Eyes”
8. Is it even right to talk about the heart, since the Bible teaches that the heart is unknowable to anyone but God? (1 Sam. 16:7; Jer. 17:9)
No one but God can see, explain, control, or change another person’s heart and its choices. There is no underlying reason why a person serves a particular lust rather than God; sin is irrational and insane. And there is no therapeutic technique that can change hearts. But the Bible teaches us that we can describe what rules the heart and speak the truth that convicts and liberates. Effective biblical ministry probes and addresses why people do things, as well as what they do. Jesus’ ministry continually exposed and challenged what people lived for, offering himself as the only worthy ruler of the heart.
For example, 1 Samuel 16:7 says that man judges by externals while God judges the heart. Yet a few verses earlier, we are told that Saul visibly disobeyed God for a reason: he feared the people and listened to their voice, instead of fearing God and listening to him (see 1 Sam. 15:24). His motives are describable, even if inexplicable. There is no deeper cause for sin than sin. Jeremiah 17:9 says that the human heart is deceitful and incomprehensible to any but God, but the same passage describes how behavior reveals that people trust in idols, themselves, and others, instead of trusting in God (see Jer. 17:1-8). Scripture is frank to tell us the causes of behavior: interpersonal conflicts, for example, arise because of lusts (see James 4:1-2). If anger and conflict come from a lust, the next and obvious question is, “What do you want that now rules you”
To search out motives demands no subtle psychotherapeutic technique. People can tell us what they want. The Israelites grumbled–a capital crime–when they had to subsist on boring food. Why? They craved flavor: fish, cucumbers, melons, leeks, onions, and garlic (see Num. 11:5). Later they grumbled when they got thirsty and no oasis appeared. Why? They craved juicy foods, or foods that demanded irrigation: grain, figs, vines, pomegranates, and water (see Num. 20:5). In each case the craving reflected their apostasy from God and expressed itself in visible, audible sins. When we see the God-substitutes that claim our affections, then we see how good and necessary the grace of Jesus is in subduing hijackers and retaking the controls.