And the cares of this world, and the deceitfulness of riches, and the lusts of other things entering in, choke the word, and it becomes unfruitful.    - Mar 4:19

Failure to mortify the Flesh is a recipe for disaster as we cannot serve two masters .      Do not 'live while intoxicated' (LWI)..

Thefts, covetousness, wickedness, deceit, lasciviousness, an evil eye, blasphemy, pride, foolishness: - Mar 7:22

All of these Sins and more proceed from the Heart of the Wicked .

Being filled with all unrighteousness, fornication, wickedness, covetousness, maliciousness; full of envy, murder, debate, deceit, malignity; whisperers, - Rom 1:29

Those people who death spiral as noted in Rom 1:21 are then Filled with the Works of the Flesh which is Satanically inspired .

Their throat is an open sepulchre; with their tongues they have used deceit; the poison of asps is under their lips: - Rom 3:13

Enumeriting the specific Sins that condemn us is an important aspect of Repentance .

But have renounced the hidden things of dishonesty, not walking in craftiness, nor handling the word of God deceitfully; but by manifestation of the truth commending ourselves to every man's conscience in the sight of God .    - 2Co 4:2

Word, Truth, Conscience

For such are false apostles, deceitful workers, transforming themselves into the apostles of Christ .    - 2Co 11:13

That you put off concerning the former conversation the old man, which is corrupt according to the deceitful lusts; - Eph 4:22

We have to willingly and purposefully put off the Old Man because, though he is Dead, his memory is still in our Minds and our muscle memory contains his tendencies and habits .

Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ .    - Col 2:8

Do not let Grace Through Faith become tainted by the Rationalizations of Legalism .

For our exhortation was not of deceit, nor of uncleanness, nor in guile: - 1Th 2:3

But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin .    - Heb 3:13

Our job is to exhort one another in the Word Of God .     Those who depart from the Word will inevitably be deceived .      The sin that hardens is unbelief .      → Unbelief in the law of God .      → Unbelief in the love of God .      → Unbelief in the judgment of God .      Do not be offended by the Word ( Mat 13:21 ).      It is the sword of the Spirit ( Eph 6:17 ) and it is given to us to surgically operate on those that are weak, those who are suffering and those who are in bondage ( 2Ti 4:2 ).