"God has nowhere promised to sublimate or spiritualize the "flesh" nor to eradicate our corruptions in this life, yet it is the Christian’s duty and privilege to so walk in the spirit that he will not "fulfill the lusts of the flesh" (Gal. 5:16). Though we should be deeply humbled over our corruptions and mourn for them, yet our painful awareness of the same should not cause us to conclude we have made no spiritual growth.
An increasing realization of our native depravity, a growing discovery of how much there is within us that is opposed to God, with a corresponding despising of ourselves for the same, is one of the surest evidences that we are growing in grace. The more the light of God shines into our hearts, the more are we made aware of the filth and wickedness which indwell them. The better we became acquainted with God and learn of His ineffable purity, the more conscious do we become of our base impurity and bewail the same. That is a growing downwards or becoming less in our own esteem. And it is that which makes way for an increasing valuation of the atoning and cleansing blood of Christ, and a more frequent betaking of ourselves to that Fountain which has been opened for sin and for uncleanness. Thus, if Christ is becoming more precious to you, if you perceive with increasing clearness His suitability for such a vile wretch as you know yourself to be, and if that perception leads you to cast yourself more and more upon Him—as a drowning man does to a log—then that is clear proof you are growing in grace.
Growth is silent and at the time imperceptible to our senses, though later it is evident. Growth is gradual and full development is not reached in a day, nor in a year. Time must be allowed before proof can be obtained. We should not attempt to gauge our growth by our feelings, but rather by looking into the glass of God’s Word and measuring ourselves by the standard which is there set before us. There may be real progress even where there is less inward comforts. Am I denying myself more now than I did formerly? Am I less enthralled by the attractions of this world than I used to be? Are the details of my daily life being more strictly regulated by the precepts of Holy Writ? Am I more resigned to the blessed will of God, assured that He knows what is best for me? Is my confidence in God growing, so that I am more and more leaving myself and my affairs in His hands? Those are some of the tests we should apply to ourselves if we would ascertain whether or no we be glowing in grace.
Consider the work of mortification and seek to ascertain what proficiency you are making therein. There can be no progress in the Christian life while that work be unattended to. God does not remove indwelling sin from His people, but He does require them to make no provision unto its lusts, to resist its strivings, to deny its solicitations. His call is "mortify therefore your members which are upon the earth" (Col. 3:5), "put off concerning the former conversation the old man, which is corrupt according to the deceitful lusts" (Eph. 4:22), "abstain from fleshly lusts which war against the soul" (1 Peter 2:11), "keep yourselves from idols" (1 John 5:21). That is the lifelong task God has assigned us, for as long as we remain in this body the flesh will oppose from within and the world from without. If we become slack in the performance of this duty, sin and Satan will gain more and more of an advantage over us. But if we be faithful and diligent therein our efforts, by the Spirit’s enablement, will not be altogether in vain.
But most of our readers, perhaps all of them, will exclaim, But this is the very matter in which I meet with most discouragement, and if I am honest it appears to me that my efforts are utterly in vain. Despite my utmost endeavors, my lusts still master me and I am repeatedly brought into captivity by sin. Though such be the case that does not mean your efforts were useless. God has nowhere promised that if you do so and so indwelling sin shall become inoperative or that your lusts shall become weaker and weaker. There is widespread misunderstanding on this subject. The word "mortify" signifies put to death, but it must be carefully borne in mind that it is used figuratively and not literally, for it is a physical term applied to that which is immaterial. Through no possible process can the Christian, not with the Spirit’s help, render his lusts lifeless. They may at times appear so to his consciousness, yet it will not be long ere he is again aware that they are vigorous and active. The holiest of God’s people, in all ages, have borne testimony to the power and prevalency in their corruptions, and that to their last hour.
It needs then to be carefully defined what is meant by the word "mortify." Since it does not signify "slay or extinguish indwelling sin" nor "render lifeless your lusts," what is intended? This: die unto them in your affections, your intentions, your resolutions, your efforts. We mortify sin by detesting it: "whosoever hateth his brother is a murderer" (1 John 3:15) and just so far as we really hate our corruptions have we morally slain them. The Christian evidences his hatred of sin by mourning when it has gained an advantage over him. If it be his sincere intention and honest resolution to subdue every rising of his native depravity and the commission of every sin, then in the sight of Him who accepts the will for the deed, he has "mortified" them. Whenever the believer contritely confesses his sins to God and "forsakes" them so far as any purpose to repeat them is concerned, he has "mortified" them. If he truly loathes, grieves over, and acknowledges his failures to God, then he can say, "that which I do, I allow not" (Rom. 7:15)."
A.W. Pink