To mortify is to put to death or deprive of power.
It is mentioned 2 times.
Here in Roman's 8 and also in Col.3.
There are several means offered in scripture to accomplish this duty.
John Owen in this writing does a masterful job of getting at some of the necessary disciplines such as being spiritually minded, keeping the heart,and being diligent to serve God properly.
His other writing made into a small book.called sin and temptation also gives many helpful biblical directives.
(2.) There are a multitude of thoughts in the minds of men which are vain, useless, and altogether unprofitable. These ordinarily, through a dangerous mistake, are looked on as not sinful, because, as it is supposed, the matter of them is not so; and therefore men rather shake them off for their folly than their guilt. But they arise from a corrupt fountain, and woefully pollute both the mind and conscience. Wherever there are "vain thoughts," there is sin, Jeremiah 4:14. Such are those numberless imaginations whereby men fancy themselves to be what they are not, to do what they do not, to enjoy what they enjoy not, to dispose of themselves and others at their pleasure. That our nature is liable unto such a pernicious folly, which some of tenacious fancies have turned into madness, we are beholding alone to our cursed apostasy from God, and the vanity that possessed our minds thereon. Hence the prince of Tyrus thought he was a god, and "sat in the seat of God," Ezekiel 28:2. So it hath been with others, And in those in whom such imaginations are kept unto some better order and bounds, yet, being traced unto their original, they will be found to spring some of them immediately from pride, some from sensual lusts, some from the love of the world, all from self, and the old
ambition to be as God, to dispose of all things as we think meet.
I know no greater misery or punishment in this world than the debasing of our nature to such vain imaginations, and a perfect freedom from them is a part of the blessedness of heaven. It is not my present work to show how sinful they are; let them be esteemed only fruitless, foolish, vain, and ludicrous.
But let men examine themselves what number of these vain, useless thoughts night and day do rove up and down in their minds. If now it be apprehended too severe, that men’s thoughts of spiritual things should exceed them that are employed about their lawful callings, let them consider what proportion they bear unto those that are vain and useless.
Do not many give more time unto them than they do unto holy meditations, without an endeavor to mortify the one or to stir up and enliven the other? are they not more wonted to their seasons than holy thoughts are? And shall we suppose that those with whom it is so are spiritually minded
