I agree only God produces good, our best are as filthy rags. But sanctification is a lifelong process, or scripture wouldn't teach such. And it is also monergistic, God does the work, we do not do it with Him.
Perhaps to you, but I believe you misunderstand. Maybe the WCF will help.
Q. 77. Wherein do justification and sanctification differ?
A. Although sanctification be inseparably joined with justification, yet they differ, in that God in justification imputeth the righteousness of Christ; in sanctification his Spirit infuseth grace, and enableth to the exercise thereof; in the former, sin in pardoned; in the other, it is subdued; the one doth equally free all believers from the revenging wrath of God, and that perfectly in this life, they never fall into condemnation; the other is neither equal in all, nor in this life perfect in any, but growing up to perfection.
You see the Spirit infuses grace, which enables us to walk by the Spirit, because we cannot of our own. At regeneration, we are imputed with Christ's righteousness, and at faith we are declared righteous. The sanctification process (internal) the Spirit infuses grace
Such were some of you; but you were washed, but you were sanctified, but you were justified in the name of the Lord Jesus Christ and in the Spirit of our God. 1 Cor 6:11.
27 I will put My Spirit within you and cause you to walk in My statutes, and you will be careful to observe My ordinances. Eze 36:27.
Some people are so worried about Catholicism that it sometimes confuses a word that they seem to use.
I believe infused is the proper term.
1828 Noah Webster dictionary: INFU'SED, participle passive Poured in; instilled; steeped.
I hope you may see that differently now?
Again, I hope you can see it differently now?