Remember, Christian: Your heart is not the compass that directs Christ. His love, Word, and promises are His compass—and so they must be ours. Your salvation in Him is secure because His covenant is sure.

“Follow your heart.” We hear this time and again, the world’s mantra to find assurance in emotion and intuition. Yet this is hardly a consolation for the Christian who knows that the heart is ever-fickle and oft-misleading. When the weight of sin overwhelms, or when doubts arise, or when fears assail, what comfort is there to be had? When weary saints distrust their salvation, where can they look for assurance, rest, and peace?

The prophet Jeremiah would warn, contra the world’s call to “trust and follow your heart,” that the subjectivity of our feelings are no sure guide for our lives. “The heart is deceitful above all things, and desperately wicked: who can know it?” (Jer. 17:9). Or, to borrow the language of Samuel Rutherford, the heart is no sure compass:

Your heart is not the compass Christ saileth by. He will give you leave to sing as you please, but he will not dance to your tune. It is not referred to you and your thoughts, what Christ will do with the charters betwixt you and him. Your own misbelief hath torn them, but he hath the principle in heaven with himself. Your thoughts are no parts of the new covenant; dreams change not Christ.[1]

In a letter written in 1637 to Earlston the Younger, Samuel Rutherford penned these assuring words to remind his friend that our salvation depends on the steadfastness of Christ and not our unsteady hearts. Evidently, Earlston was a youth who felt like he was being beaten while struggling against all manner of sin and doubt. Rutherford responded to him in three ways: He encouraged Earlston to not listen to the lies of sin or Satan; he implored Earlston to turn to Christ as the Physician of his soul; and he offered several compelling ways to fight such doubts of the heart.

Beware the Lies of Sin and the Devil

Satan “cometh not, but for to steal, and to kill, and to destroy,” while Jesus comes, “that they might have life, and that they might have it more abundantly” (John 10:10). Is it any surprise that Satan would aim to steal, kill, and destroy the Christian’s assurance in Christ? And what better tactic or strategy is there for the devil to employ than that of temptation? Is there any experience more subjectively deceiving than the momentary and fleeting pleasure of sin followed by extraordinary remorse, regret, and doubt?

The Apostle Paul had cautioned his youthful protégé Timothy to, “Flee also youthful lusts: but follow righteousness, faith, charity, peace, with them that call on the Lord out of a pure heart” (2 Tim. 2:22). Rutherford’s warning to Earlston was similar:

I have seen the devil, as it were, dead and buried, and yet rise again, and be a worse devil than ever he was; therefore, my brother, beware of a green young devil, that hath never been buried. The devil in his flowers (I mean the hot, fiery lusts and passions of youth) is much to be feared: better yoke with an old gray-haired, withered, dry devil. For in youth he findeth dry sticks, and dry coals, and a hot hearthstone; and how soon can he with his flint cast fire, and with his bellows blow it up, and fire the house! Sanctified thoughts, thoughts made conscience of, and called in, and kept in awe, are green fuel that burn not, and are a water for Satan’s coal.[2]

To return to youthful lusts and passions is to dig up the devil. To do so is not only to give into the demands of a wicked enemy, but to return to an old life, though we be new creations in Christ. By turning back to Satan and sin, the Christian essentially gets on the ground alongside Satan’s burning coals and blows upon them with his own breath, causing the consuming flames of temptation and sin to burn brighter and spread. Is it any surprise that sin produces doubt in the heart?

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