Believers in Christ should have accepted the Gospel, the salvation of God, Christ our Lord Jesus by faith and should know very well not to sin anymore. Hence the true righteousness, the righteousness of God is what we should seek.
Yet, we do fail from time to time, but that is not an excuse. Some said, it is impossible, even after becoming a believer, to NOT sin. Then, this person is still loving his sin. Not willing to let Christ be the center figure of his life. Such is also lack of faith, therefore not able to see the truth, because he wants to see first before he believes. Consciously or not, he memorizes this statement(not verse): It's okay to sin, because God will forgive you.
However, if we sin even after being saved, we must seriously come before God to honestly repent, and not try to reason a way out of it.
It is an understatement that non-believers, not knowing God, hence not knowing the righteousness of God, would be able to not sin.
So to paraphrase Augustine's statements:
The following two statements are wrong...
1. It is impossible for a person to sin in his earthly life after he obtained salvation.
2. It is impossible for a person to be sinless in his earthly life after he obtained salvation.
Usually believers who do not think it is possible to NOT to sin are those who are still living in sin, using the notion that humans are weak to encourage themselves, dazing themselves with little or no guilt at all because God forgives sinners. They knew all the tragedy of sin, but they take the salvation of God so likely. Such, is not the righteousness of God. Asking God for forgiveness and making photocopies of forgiveness coupons are two different things.
This is also why Islam is founded so successfully. Nevertheless, God's plan does not change. One cannot look at bad christians only and ignore what God has revealed in the new testament or think God has changed His mind. Christ our Lord Jesus is the center figure of the whole mystery of God's plan in history. The Oneness of the Holy Trinity is God's special revelation to us all.
[@more@]