When Adam obeyed Satan, he became servant of sin. In fact, all of mankind became servant of sin, a servitude which should be obvious to any observer of human nature.. As with any conquered country, the children are also captive. The human desire to follow one's own inclinations can be seen everywhere. The sons of God became the sons of Satan.
Romans 6:16 Know ye not, that to whom ye yield yourselves servants to obey, his servants ye are to whom ye obey; whether of sin to death, or of obedience to righteousness?
The Father has arranged for a wonderful way for humanity to be translated from sons of Satan to sons of God. The price was enormous--the death of Jesus on the cross, bearing all the sins of the world for all time. However, the Father's love and the love of Jesus was so great that God's plan went forward in spite of the high price.
Now, any who will receive Jesus can be made free from sin and become servants of righteousness.
Romans 6:16 Know ye not, that to whom ye yield yourselves servants to obey, his servants ye are to whom ye obey; whether of sin to death, or of obedience to righteousness?
When a person is born again, it is by believing on the Son of God. This is a birth that is given freely to any who will receive it. The born-again person is, from that time forward, as child of God.
From the time of being born again, the Christian has the choice of remaining servant of sin or allowing his or her mind to be renewed. Each Christian has the choice of either learning righteousness now or following the ways of the flesh for now and waiting for righteousness until later. The Bible is quite clear that there are huge problems for those who wait for righteousness until later, and they miss out on the best blessing of salvation.