That idea is Gnosticism which infiltrated Christianity through the influence of Augustine.
What we do is a reflection of who we are, a reflection of our character, a reflection of what is in our heart.
A heart that is pure with the love of God written upon will not produce the fruit of sin.
This is why those whom argue in favour of ongoing wickedness in salvation, often dressed up as "sinning less," have actually bought into a counterfeit salvation where they deny heart purity.
The Apostle Paul wrote...
Tit 2:14 Who gave himself for us, that he might redeem us from all iniquity, and purify unto himself a peculiar people, zealous of good works.
2Co 5:17 Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.
John wrote...
1Jn 3:6 Whosoever abideth in him sinneth not: whosoever sinneth hath not seen him, neither known him.
One cannot be "sinning" and "saved" at the same time. Salvation is FROM sin, not in it.
If Satan can convince people of "salvation in sin" and thus give people an assurance that they are saved whilst they still work iniquity, then those people are ensnared by "ye can sin and not surely die" and are in a very dangerous position for a lie serves to immunise their mind to the truth.