William Gurnall on the object and purpose of sin:

O sirs, take the right notion of sin, and you will hate it.  The reason why we are so easily persuaded to sin is, because we understand not the bottom of [Satan’s] design in drawing a creature to sin.  It is with men in sinning as it is with armies in fighting.  Captains beat their drums for volunteers, and promise all that list, pay and plunder; and this makes them come trowling in.  But few consider what the ground of the war is, against whom, or for what.  Satan enticeth to sin, and gives golden promises [of] what they shall have in his service, with which silly souls are won.  But how few ask their souls, Whom do I sin against?  What is the devil’s design in drawing me to sin?  Shall I tell thee?  Dost thou think it is thy pleasure or profit he desires in thy sinning?  Alas, he means nothing less, he hath greater plots in his head than so.  He hath, by his apostasy, proclaimed war against God, and he brings thee, by sinning, to espouse his quarrel, and to jeopard the life of thy soul in defence of his pride and lust; which that he may do, he cares no more for the damnation of thy soul, than the great Turk doth to see a company of his slaves cut off for the carrying on of his design in a siege.  And darest thou venture to go into the field upon his quarrel against God?  O earth, tremble thou at the presence of the Lord.  This bloody Joab sets thee where never came any off alive.  O stand not where God’s bullets fly.  Throw down thy arms, or thou art a dead man.  Whatever others do, O ye saints, abhor the thoughts of sinning willingly; which when you do, you help the devil against God.  And what more unnatural than for a child to be seen in arms against his father?

—William Gurnall, The Christian in Complete Armour (Banner of Truth Trust, 2002), 1:182.