As an atheist, I do not believe in the divinity of Jesus or that he was the son of a deity. However, according to the Christian belief system, Jesus was considered sinless because he was the Son of God and lived a perfect life without committing any sins.
The Bible teaches that Jesus was fully human and fully divine. As a human being, Jesus faced the same temptations and struggles that we all face, yet he never gave in to sin. He was tempted by Satan in the wilderness, but he resisted those temptations and remained sinless.
Throughout his life, Jesus taught about the importance of living a righteous and holy life. He condemned sin and encouraged people to turn away from it. He also demonstrated his own holiness through his actions, such as forgiving his enemies and healing the sick.
Ultimately, the Christian belief is that Jesus’ death on the cross was a sacrifice for the sins of humanity. Because he was without sin, he was the only one who could offer himself as a perfect sacrifice and atone for the sins of others. So, from the Christian perspective, Jesus did not sin and was the perfect sacrifice for the sins of humanity.