No sin is more apt to insinuate itself into our hearts, and duties, than hypocrisy.
We, of all men, are most in danger to be deceived by it: For our employment lying in, and about spiritual things, we are, on that account, stiled spiritual men (Hosea 9:7). But it is plain, from that very place, that a man may be objectively a spiritual, and all the while subjectively a carnal man. Believe it, brethren, it is easier to declaim, like an orator, against a thousand sins of others, than it is to mortify one sin, like Christians, in ourselves; to be more industrious in our pulpits, than in our closets; to preach twenty sermons to our people, than one to our own hearts.
The Whole Works of the Reverend John Flavel, 6:568.
The first great secret of holiness lies in the degree and the decisiveness of our repentance. If besetting sins persistently plague us, it is either because we have never truly repented, or because, having repented, we have not maintained our repentance. It is as if, having nailed our old nature to the cross, we keep wistfully returning to the scene of its execution. We begin to fondle it, to caress it, to long for its release, even to try to take it down again from the cross. We need to learn to leave it there. When some jealous, or proud, or malicious, or impure thought invades our mind we must kick it out at once. It is fatal to begin to examine it and consider whether we are going to give in to it or not. We have declared war on it; we are not going to resume negotiations. We have settled the issue for good; we are not going to re-open it. We have crucified the flesh; we are never going to draw the nails.
The Message of Galatians, 151–152.
Mortification of sin is a duty always incumbent on us in the whole course of our obedience. This the command testifieth, which represents it as an always present duty. When it is no longer a duty to grow in grace, it is so not to mortify sin. No man under heaven can at any time say that he is exempted from this command, nor on any pretence; and he who ceaseth from this duty lets go all endeavours after holiness. And as for those who pretend unto an absolute perfection, they are of all persons living the most impudent, nor do they ever in this matter open their mouths but they give themselves the lie.
The Works of John Owen, 3:541.
We mortify sin by cherishing the principle of holiness and sanctification in our souls, labouring to increase and strengthen it by growing in grace, and by a constancy and frequency in acting of it in all duties, on all occasions, abounding in the fruits of it. Growing, thriving, and improving in universal holiness, is the great way of the mortification of sin. The more vigorous the principle of holiness is in us, the more weak, infirm, and dying will be that of sin. The more frequent and lively are the actings of grace, the feebler and seldomer will be the actings of sin. The more we abound in the ‘fruits of the Spirit,’ the less shall we be concerned in the ‘works of the flesh.’ And we do but deceive ourselves if we think sin will be mortified on any other terms.
Works of John Owen, 3:552.
The apostle gloried and rejoiced in the cross of Christ. His heart was set on it. It crucified the world to him, making it a dead and undesirable thing (Gal 6:14). The baits and pleasures of sin are all things in the world, “the lust of the flesh, the lust of the eyes, and the pride of life.” By these sin entices and entangles our souls. If the heart is filled with the cross of Christ, it casts death and undesirability on them all, leaving no seeming beauty, pleasure, or comeliness in them. Again, Paul says, “It crucifies me to the world and makes my heart, my affections, and my desires dead to all these things. It roots up corrupt lusts and affections, and leaves no desire to go and make provision for the flesh to fulfill its lusts.”
Indwelling Sin in Believers: Abridged and Made Easy to Read, 99–100 ; original: vol. 6, 250–251.