Counterfeit Repentance (part 2)

"Another deceit about repentance is resolution against sin.
A person may purpose and make vows, yet be no penitent. `Thou saidst, I will not transgress' (Jer. 2.20). Here was a resolution; but see what follows: `under every green tree thou wanderest, playing the harlot'. Notwithstanding her solemn engagements, she played fast and loose with God and ran after her idols. We see by experience what protestations a person will make when he is on his sick-bed, if God should recover him again; yet he is as bad as ever. He shows his old heart in a new temptation.

Resolutions against sin may arise:
(1) From present extremity; not because sin is sinful, but because it is painful. This resolution will vanish.
(2) From fear of future evil, an apprehension of death and hell: `I looked, and behold a pale horse: and his name that sat on him was Death, and Hell followed with him' (Rev. 6.8). What will not a sinner do, what vows will he not make, when he knows he must die and stand before the judgment-seat? Self-love raises a sick-bed vow, and love of sin will prevail against it. Trust not to a passionate resolution; it is raised in a storm and will die in a calm."

From The Doctrine of Repentance, by Thomas Watson.