The work of keeping our heart is not an easy work, but it is an attainable work, and we can be assured that it is an attainable work because God has promised that it is a work that He Himself is working in us by His Spirit. If we stand firm, it is because we stand firm in the Lord (Philippians 4:1), knowing that “it is God who works in [us], both to will and to work for his good pleasure” (Philippians 2:13).
As the armies of Saruman marched against Rohan in J.R.R. Tolkien’s masterful The Lord of the Rings, the citizens of Rohan make their stand in the Hornburg, a fortress of last defense at the mouth of Helm’s Deep. The Hornburg was the heart of Rohan’s defense, so that if the Hornburg fell, Rohan would be finished. Similarly, the heart of a man might be compared to that fortress of last defense. The heart is the battleground of your soul, which is why the Proverbs warn us to “keep your heart with all vigilance, for from it flow the springs of life” (Prov. 4:23). If the heart ultimately falls in the spiritual battle, a man is finished. He will become “like a city broken into and left without walls” (Prov. 25:28).
Proverbs 4:23 uses two different Hebrew words that might both be translated “to keep,” so that one might even translate this verse “keep your heart with all keeping.” The first word has to do with “keeping watch,” while the second has the sense of “keeping guard.” Given this emphasis on “keeping,” it goes without saying that we ignore this scriptural warning to our own peril. But what does it mean to “keep our hearts,” and what practical steps might we take to actually go about it? There are basically three things involved in keeping our hearts; we might call them surveilling our hearts, maintaining our hearts, and defending our hearts.
Surveillance is an absolutely necessary component in the work of keeping our hearts. To do surveillance is to keep a close watch on something—think of the police on a stakeout or a sentry watching on a city wall. Simply being aware and paying close attention to our hearts is of first importance. The word translated “keep” in this verse has the sense of “keeping watch over.” If we are to keep our hearts, we must do that first work of spiritual surveillance, so that we know our hearts. When we think of surveillance in an ancient city, we probably think first of a lookout or sentry standing guard, ready to sound an alarm. And that is an absolutely necessary part of our surveillance. We must be on the lookout for the schemes of our enemy “so that we would not be outwitted by Satan” or “ignorant of his designs” (2 Cor. 2:11). Yet we must recognize that when it comes to surveillance, we must not only look outward. We must also look inward. We must be aware of the places where the fortress of our heart may be weak and vulnerable to attack. That is why the work of keeping our hearts must involve not only spiritual surveillance but also the constant work of spiritual maintenance.