It' not really about the ability to stop sinning, it's about whether or not someone wants to do it.
We know this because even the unsaved get themselves off of alcohol and drugs to avoid the miserable consequences of living that horrid lifestyle, the ruination is their motivator.
So, there are those who choose to stop a sin when it benefits them to do it.
With Christ we stop and say away from sin because we know it displeases the Holy God. The Holy Spirit in us makes us miserable in sin, so we either avoid it, or if we fall because we have a weak moment, we are miserably guilty until we confess and turn from it.
It matters to God why we stop sinning!
Notice in other verses says, "when he comes to me to ask forgiveness."
Luke 17:3-4 "…3 Watch yourselves. If your brother sins, rebuke him; and if he repents, forgive him. 4 Even if he sins against you seven times in a day, and seven times returns to say, ‘I repent,’ you must forgive him.”"
Leaving out the confession and cleansing process leaves the one who sins smug in his sin. We must not enable the offender by forgiving when they are not sorry, that would be to thwart the purpose of God.
We must not leave out the steps of reconciliation. If the brother sins, rebuke him and forgive him IF he repents. If he does not repent, then walk away and leave him to God.
We do no one any favors if we share our forgiveness before someone is sorry. We actually help to harden their hearts, causing them to think they can do anything they like, no matter how evil and they will still be acceptable to God.
When we forgive people who are not sorry, we are sending a wrong message about Christ. Christ will not forgive those who are not broken over their sin and will not confess it.
God even told believer to confess their sin to be cleansed in 1 John 1:9. We are to confess to be forgiven and cleansed.
1 John 1:9
"9 IF we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness."
When we encounter people who are nice to some people and mean to others, we have encountered a pretender.
Loving people are always that way to everyone, they don't choose to be nice to some and mean to others, because their love is genuine.
Loving people speak the truth because they are deeply connected to Christ, they love Him above all else and others so much they can't withhold sharing God's truth with them.
The self righteous person hates truth, they prefer a false image of self than facing truth. Those who can face truth about themselves, grow in holiness, it is in the admitting truth about ourselves that helps us become cleansed. Christ will not cleanse someone who has a high opinion of themselves.
Selfish people are more about looking good on the outside, deeply invested in appearing righteous in front of people. The righteous man wants to actually be holy, through continual cleansing of faults and does this by facing truth about themselves and others. The righteous man will choose the ways of God over worldly ways, when no one is watching.
Love is a state of being within a person, it is not a manipulation tactic to gain approval or attention.
1 Corinthians 13:4-8
"4 Love is patient, love is kind and is not jealous; love does not brag and is not arrogant, 5 does not act unbecomingly; it does not seek its own, is not provoked, does not take into account a wrong suffered, 6 does not rejoice in unrighteousness, but rejoices with the truth; 7 [a]bears all things, believes all things, hopes all things, endures all things.
8 Love never fails; but if there are gifts of [b]prophecy, they will be done away; if there are tongues, they will cease; if there is knowledge, it will be done away."
