Not to be daily employing the Spirit and new nature for the mortifying of sin is to neglect that excellent succor which God has given us against our greatest enemy. If we neglect to make use of what we have received, God may justly hold his hand from giving us more. His graces, as well as his gifts, are bestowed on us to use, exercise, and trade with. Not to be daily mortifying sin is to sin against the goodness, kindness, wisdom, grace, and love of God, who has furnished us with a principle of doing it.
For true conversion doth not consist in putting away great and outward sins only, but in descending deeply into your own self, searching into the inmost recesses of the heart, the secrets and closets, all the windings and turnings thereof; changing and renewing them throughout, with the grace that is given you: and so, by faith, you are converted from self-love to Divine love; from the world and all worldly concupiscences, to a spiritual and heavenly life; and from a participation of the pomps and pleasures thereof, to participating the merits and virtues of Christ, by believing his word, and walking in his steps.
Pleasure, in itself harmless, may become mischievous, by endearing to us a state which we know to be transient and probatory, and withdrawing our thoughts from that of which every hour brings us nearer to the beginning, and of which no length of time will bring us to the end. Mortification is not virtuous in itself, nor has any other use, but that it disengages us from the allurements of sense. In the state of future perfection, to which we all aspire, there will be pleasure without danger, and security without restraint.