We read in the Bible that on the one hand believers continue to sin, but on the other hand they have been set free from sin.
If we say that we have no sin, we deceive ourselves, and the truth is not in us.If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.If we say that we have not sinned, we make him a liar, and his word is not in us. (1 John 1:8-10).
Whosoever is born of God doth not commit sin; for his seed remaineth in him: and he cannot sin, because he is born of God (1 John 3:9).
This sounds like a contradiction, and Christian theologians have been trying to explain it for centuries.
This contradiction can only be explained by understanding Yahweh's purpose. He reflected the spiritual through the physical (Romans 1:19,20). Therefore, spiritual birth (birth from God leading to sinlessness according to John) can be understood through the birth of a child. The birth of a child goes through 3 stages (following the pattern of the Tabernacle): fertilization, intrauterine development, and birth into the world. Note that miscarriages can occur during intrauterine development, for example, if the mother abuses alcohol. In spiritual birth, a person hears and receives the Word of Truth (fertilization), grows and is formed in knowledge (intrauterine development), and begins to live spiritually on his own when Yahweh reveals truth or gives him spiritual understanding (spiritual birth). This process is described in the Savior's parable of the sower (Matthew 13:1-23).
From this we see that there are 2 groups of believers. Those who understand - they were born and cannot give up God or go back to their mother's womb (John 3:3,4) and do not sin. Those who are not yet spiritually mature and are in the “spiritual womb” can refuse God and not be born Spiritually (2 Peter 2:20) and continue to sin. Of course, there is also a large group of people who think they believe in the Truth, but have not heard the Truth, but believe in interpretations and traditions.
More detailed explanation with more witnesses is in this lecture which includes a PowerPoint presentation (from 1hr23min until 2hr02min):