The Advantage of Examining Indwelling Sin

John Owen, to conclude Chapter 6 of The Nature, Power, Deceit, and Prevalence of the remainders of Indwelling-Sin in Believers, Part 2: The Power and Efficacy of Indwelling Sin, illuminates the advantage of illuminating our own indwelling sin (c.f. Romans 7:14-25):

This is the sum of what we shall offer unto this acting of the law of sin, in a way of fighting and warring against our souls, which is so often mentioned in the Scriptures; and a due consideration of it is of no small advantage unto us, especially to bring us unto self-abasement, to teach us to walk humbly and mournfully before God. 

There are two things that are suited to humble the souls of men, and they are, first, a due consideration of God, and then of themselves—of God, in his greatness, glory, holiness, power, majesty, and authority; of ourselves, in our mean, abject, and sinful condition.

Now, of all things in our condition, there is nothing so suited unto this end and purpose as that which lies before us; namely the vile remainders of enmity against God which are yet in our hearts and natures. And it is no small evidence of a gracious soul when it is willing to search itself in this matter, and to be helped therein from a word of truth; when it is willing that the word should dive into the secret parts of the heart and rip open whatsoever of evil and corruption lies therein.

…Most men love to hear of the doctrine of grace, of the pardon of sin, of free love, and suppose they find food therein; however, it is evident that they grow and thrive in the life and notion of them. But to be breaking up the fallow ground of their hearts, to be inquiring after the weeds and briars that grow in them, they delight not so much, though this be no less necessary than the other. 

..It were wished that we would all apply our hearts more to this work {of searching our own souls for indwelling sin}, even to come to a true understanding of the nature, power, and subtlety of our adversary, that our souls may be humbled; and that — 

In walking with God. His delight is with the humble and contrite ones [Isa. 57:15], those that tremble at his word [Isa. 66:2], the mourners in Zion [Isa. 61:3]; and such are we only when we have a due sense of our own vile condition.  This will beget reverence of God, a sense of our distance from him, admiration of his grace and condescension, a due valuation of mercy, far above those light, verbal, airy attainments {of perfection}, that some have boasted of.

In walking with others. It lays in provision to prevent those great evils of judging, spiritual unmercifulness, harsh censuring, …This {self-examination of indwelling sin}, I say, will lead us to meekness, compassion, readiness to forgive, to pass by offenses; even when we shall "consider" what is our state, as the apostle plainly declares (Gal. 6:1). The man that understands the evil of his own heart, how vile it is, is the only useful, fruitful, and solid believing and obedient person. 

Owen, John. Indwelling Sin, Part 2: The Power and Efficacy of Indwelling Sin.  Overcoming & Temptation. Edited by Kelly M. Kapic and Justin Taylor.  Crossway Books, 2006. pg. 282-283.