“Those who have been born into God’s family do not make a practice of sinning, because God’s life is in them. So they can’t keep on sinning, because they are children of God.” (1 John 3:9 NLT).

NEW PRACTICES NOT YET PERFECTION
John here describes the fruit of being born again, namely, that those with God’s life in them, no longer make a practice of sin. Sin is no longer their habit. This is not the precondition of salvation. For salvation is by grace alone through faith alone in Christ alone. Yet, the fruit of having received this salvation is that the child of God is putting off the old nature with its sinful desires and putting on the new nature, which loves God and neighbor.
 
There is a positional truth and an experiential truth in view here. First, the believer is already counted righteous before God positionally in Christ. But experientially, that same believer is still working out their salvation in this world, putting off the old man and putting on the new. So, perfection, complete sinlessness, will not be the believer’s experience until the glorified body is received. On that day, position and experience will be the same.
 
Until that day, let us work out what God is working in us (Phil. 2:12-13), knowing that Christ is our Advocate before the Father and depending on Him to complete that which He began in us.