In my preparation for preaching I looked at Hebrews 12 and thought about the verse describing, “the sin that clings so closely,” or as the NIV puts it, “the sin that so easily entangles.” I read this section by an old Puritan writer here. It is and is powerful and challenging and allows us to gave clearly at our sin as well as stimulating us to repentance:
As an aside Puritan writer Thomas Watson has some interesting points regarding the nature of a “besetting sin”…
Take heed of your besetting sin, that which your nature and constitution most incline to. As in the hive there is a master bee—so in the heart there is a master sin. “I kept myself from my iniquity.” Ps 18:23. There is some sin that is a special favorite, the darling sin which lies in the bosom—and this bewitches and draws away the heart. O beware of this!
 That sin which a man most nourishes, and to which all other sins are subservient—is the sin which is most tended and waited upon. The Pharisees’ darling sin was vainglory, all they did was to feed the sin of pride. When they gave alms they sounded a trumpet, that they might admired by others. Matthew 6:2. If a stranger had asked why this trumpet sounded? The answer was, the Pharisees are going to give alms to the poor. Their lamp of charity was filled with the oil of vainglory. Matthew 23:5. All their works they did to be seen by men. Pride was their bosom sin. Oftentimes covetousness is the darling sin; all other sins are committed to maintain this. Why do men equivocate, oppress, defraud, take bribes—but to uphold covetousness?
 The sin which a man hates to be reproved—is the darling sin. Herod could not endure to have his incest spoken against; if John the Baptist meddles with that sin, it shall cost him his head.
 That sin which has most power over a man, and most easily leads him captive—is the beloved of the soul. There are some sins which a man can better put off and repulse; but there is one sin which he cannot deny—but is overcome by it: this is the bosom sin. The young man in the gospel had a besetting sin which he could not resist, and that was the love of the world; his silver was dearer to him than his Savior. It is a sad thing a man should be so bewitched by a lust—that he will part with the kingdom of heaven to gratify it!
 The sin which men use arguments to defend—is the darling sin. To plead for sin, is to be the devil’s attorney. If the sin is covetousness, and we vindicate it; if it is rash anger, and we justify it, saying (as Jonah 4:9), “I do well to be angry,” this is the besetting sin.
 That sin which most troubles a man, and flies in his face in an hour of sickness and distress—is the beloved sin. When Joseph’s brethren were distressed, their sin in selling their brother came to remembrance. Gen 45:3. So, when a man is upon his sick-bed, conscience says, “Do not you remember how you have lived in such a sin, though you have been often warned—yet you would not leave it?” Conscience reads a secret lecture upon the darling sin.
 The sin which a man is most unwilling to part with—is the darling sin. Jacob could of all his sons, most hardly part with Benjamin. “Joseph is not, and Simeon is not, and you will take Benjamin away.” Gen 13:36. So says the sinner, “this and that sin have I parted with; but must Benjamin go? Must I part with this delightful sin? That pierces my heart!” It is the Delilah, the beloved sin. Oh, if sin is such a deadly evil, dare not to indulge any bosom sin, which is the most dangerous of all; and, like a cancer striking to the heart, which is mortal. One darling sin lived in, sets open a gap for Satan to enter.