An injury that comes through allowing any corruption to prevail, is that it keeps the soul lean and low, and makes it a cripple when it comes to duties. It not only mars confidence and cheerfulness in duty, but diligence and activity also. It insensibly hardens the heart. What a fearful security and stupidity brought one sin upon David? Where was David’s tenderness now, when he can plot poor Uriah’s death? It is a sickness to the soul, for sin is the soul’s disease, that enervates its strength and makes it languish. What is said of whoredom and wine, is true of every sin, they take away the heart, yes, and the hand too. As the man is like the silly dove without heart, and cannot behave himself rightly in God’s presence, so he comes no speed at God’s work, for he works with damaged powers; his foul hands blacken holy duties; his fingers drip much sin upon them; the old man leaves the print of his heels on them. O what is it that keeps you out of heaven, at least from seeing it in the distance. It is some sin that besets you, and hinders your progress heavenward. How few steps have you advanced for these many days (Hebrews 12:1-2)? Some weight presses you down, some corrupt affection, like a long garment entangles you; or you stumble and fall often in the way. It is not so much external duties, as the secret exercise of mortification, that keeps grace lively; and when this is neglected and any sin prevails, grace withers, and often the Lord blasts a man’s gifts too, or if gifts are left intact, they are left as a snare. This was Solomon’s snare, that when he was pursuing vanity, his wisdom remained with him (Ecclesiastes 2:9). It is the curse of many this day, and that which hardens them in their ill way, that their gifts and learning remain with them.