Paul testified to present victory over sin,'
For the law of the Spirit of life in Christ Jesus has made me free from the law of sin and death' Rm 8:2.
To be "free from the law of sin and death" means that Paul was not ultimately condemned for his sin, not that he was not still subject to the consequences of sin in this life. (I.E. Paul still died.)
This is a 'damned if you do, damned if you don't' situation. If one refuses to give an answer to the above question, having professed entire sanctification, you become the target of all types of unwanted criticism.
If, on the other hand, one confesses humbly that by the grace of God they have been kept from sinning, they get hammered by criticism as well.
"Entire sanctification" as the "holiness movement" defines it here though, is a false doctrine. The grace of God does keep the redeemed from living lifestyles of sin; (i.e. believers are not "addicted to sin") but God does not make us sinless this side of the grave either. If we could be sinless in this life; there'd be no predicated reason for Christ to have risen from the dead. "And if Christ be not raised, you are yet in your sin and your faith is in vain."
And this is so because the regeneration of the indwelling of the Holy Sprit does not make us the incarnation of God. This is why Scripture describes those as "Christ like" but in this life, never bearing the sinless nature of Christ. The obvious evidence there of, being that we still die!
Christ though, if he wasn't the atoning sacrifice for sin; would have been bodily immortal. He only died because of the severance of His Divine nature from his human nature. And without the human nature, he could not have been the appropriate sacrifice and without the Divine nature, he would not have been sufficient to take on the wrath of God.
So, my answer is this, by the power & presence of the Holy Spirit, I have been kept from falling into sin, i.e. from willfully, transgressing the Law of God.
The law is the schoolmaster that points sinners to Christ. The only thing the Law of God can do is condemn you because that's what it was designed to do. Its purpose was to make sin definable. It gave definition to what corruption produced.
Scripture says that "out of the mouth of two or three witnesses, let all things be established". Well we have "witnesses" in this life.
1. Creation testifies to the attributes of God, including His eternal Godhead and power. Actually also conveying to us the redemption plan in parabolic form. Thus we are "without excuse"; although on the positive side of this; it also means that none of humanity has been left without a witness.
2. Human conscience testifies to the morally holy nature of God; because Adam and subsequently all of humanity is created in God's image.
3. Written revelation (Scripture) explains to humanity the redemption plan that's necessary, because of the moral holiness of God and the corruption the knowledge of good and evil has brought into this world.
Yet we all by nature still willfully transgress; even in the midst of the desire not to! This is why Scripture has statements like:
What
is man, that he should be clean? and
he which is born of a woman, that he should be righteous?
Behold, he puts no trust in his saints; yea, the heavens are not clean in his sight.
How much more abominable and filthy
is man, which drinks iniquity like water?
Job 15:14-16
By the Law of God I mean, the Law of Love. Through God, I have loved the Lord with all my being and my neighbor as myself. To Him be the glory.
Now come the stones!
And the stones come from the fact that you know in your conscience that you are not sinless.
So thus the question really isn't about how righteous you perceive yourself to be; but whether or not sanctification has produced the fruit of security through faith. Do you trust that Christ's atonement is sufficient? For that is really the only place any of us find security.
And thus why the answer to Paul's prayer was: "My grace is sufficient for you."