From my vantage point, the discussion is all about imputation. I know that others disagree. (Otherwise we wouldn’t be having this discussion :>)
The bottom line, however, remains: have they or have they not persevered.
What are ways to persevere:
1. Have you sin not counted against you, so that you have a judicial righteousness and not a righteousness of your own.
2. Live a life with zero sin, so that no sin can be held against you.
3. Life a life which includes sin, but balance that sin by a more weighty portion of righteous acts that cancels out the sin.
4. Combinations of the above
As David says, “Ps 32:2 - Blessed is the man whose sin the Lord does not count against him and in whose spirit is no deceit.”
2 Grace to you and peace be accomplished in the knowledge of God and of Christ Jesus our Lord: 3 As all things of his divine power which appertain to life and godliness, are given us, through the knowledge of him who hath called us by his own proper glory and virtue. 4 By whom he hath given us most great and precious promises: that by these you may be made partakers of the divine nature: flying the corruption of that concupiscence which is in the world. 5 And you, employing all care, minister in your faith, virtue; and in virtue, knowledge; 6 And in knowledge, abstinence; and in abstinence, patience; and in patience, godliness; 7 And in godliness, love of brotherhood; and in love of brotherhood, charity. 8 For if these things be with you and abound, they will make you to be neither empty nor unfruitful in the knowledge of our Lord Jesus Christ. 9 For he that hath not these things with him, is blind, and groping, having forgotten that he was purged from his old sins. 10 Wherefore, brethren, labour the more, that by good works you may make sure your calling and election. For doing these things, you shall not sin at any time.(2 Peter 1)
Colossians Chapter 1 has the same idea.