Jesus said,
Jhn 6:47, Verily, verily, I say unto you, He that believeth on me hath everlasting life.
Actually, in order to keep from sinning in the flesh we must needs abide in Him through faith in Jesus and what He did for us on the Cross. So then, our behaviour of no longer sinning in the flesh is dependent on us believing in what He did for us on the Cross. John 15:1-8.
It is no doctrine of men; it is rather a doctrine of God.
John 8:31-36, 1 John 3:5-9, Hebrews 10:10-14, 1 Peter 5:10-12, 1 Thessalonians 5:23-24; Jude 1:24, 2 Peter 1:10, 1 John 2:10; 1 John 3:7, 1 John 3:3, 1 John 2:6.
There is a certain level of holiness that a man can attain to in Christ. I would not call it sinless perfection; for there is still the element of indwelling sin as a factor, in one who has been delivered from the power of sin. Sin has been rendered dead within me; it no longer has any say over my behaviour (Romans 7:8, Galatians 5:24, Romans 6:6).
As such, it identified us as sinners (Romans 3:20), it is a schoolmaster to lead us to Christ. It shows us that we are sinners in need of a Saviour. if you do not love the Lord your God with all of your heart, soul, mind, and strength, then you have committed the greatest sin; for you have broken the greatest commandment.
It is possible through the Cross to obey this commandment. Grace endowed means that the love of the Lord is shed abroad in your heart. If you love according to this love, you fulfill the law, and are set free from sin.
If you do not have Jesus in your heart, then this commandment shows you your sin and that you are still a man in need of a Saviour.
What does the life of a man look like who loves the Lord with all of his heart, mind, soul, and strength?
I think it would be a life that pleases God at every venue.
We can live that life in Christ.
Luke 1:37, Ephesians 3:19-20.