Yes, everyone is a sinner.
for there is no man who does not sin.
1 Kings 8:46  NASB
(6 more references)


No, Christians are sinless.
(And so are some non-Christians.)

Nevertheless death reigned from Adam until Moses, even over those who had not sinned in the likeness of the offense of Adam, who is a type of Him who was to come.
Romans 5:14  NASB

No one who abides in Him sins; no one who sins has seen Him or knows Him.
1 John 3:6  NASB

No one who is born of God practices sin, because His seed abides in him; and he cannot sin, because he is born of God.
1 John 3:9  NASB

We know that no one who is born of God sins; but He who was born of God keeps him, and the evil one does not touch him.  (NASB)
1 John 5:18  NASB

The one who does good is of God; the one who does evil has not seen God.
3 John 11  NASB


SAB Contradiction 411


General reflection
Do Christians sin? Yes, sometimes they do. One may ask: “If that is true what sense does it make to become a Christian at all?” Well, of course this is a philosophical question. It is in practice true that accepting Jesus Christ has a great and positive impact on our human nature. More than we might suppose or imagine. But yes, sometimes Christians do seriously wrong. The point is that the power of sin does not rule anymore. There is no reason to remain a victim of sin. If something goes wrong the best resistance against it is to acknowledge and to make things right with people (if possible) and God. (1 John 1:9) 


Mortal sin
With regard to the supposed contradictions: Only the critical texts relevant for discussion have been printed above under the head “No, Christians are sinless.” We have to warn the reader previously that the critic reads his texts dogmatically and that is mortal sin in reading biblical texts that are written in ordinary language. Let’s have a look.


Romans 5:14
It is immediately clear that the full text is not at all in conflict with the teaching that all people sin (Christians also, see above). There is only mention of people who had not sinned just like Adam, … but under different circumstances, of course. Apparently this was not read properly by the critic. He only may have seen the clause “those who had not sinned”, and “Yes, again a fine Bible Contradiction!” he might have thought. I’m sorry to say, but that’s not the way it should be.  
No Bible Contradiction


1 John passages
There are three instances in the First Letter of John that give the impression that indeed Christians don’t sin. However this conclusion should not be arrived at too hastily. There is a real interpretation/translation question here. John uses in these cases a so called gnomic present: this is a possibility to express customary action. In these cases: sinning by habit, practicing sin; instead of sinning sometimes. An interesting example of a gnomic present may be what the oldest son said to his father after the return of his younger brother (Luke 15:29): “Look! For so many years I serve you …” Literally: “Look! For so many years I am your slave …” Not amusing for a father to hear, is it?

1 John 3:6
With gnomic present: “No one who abides in Him practices sin; no one who sins by habit has seen Him or knows Him.”  In the first clause there are two simultaneous actions: abide in Him and practices sin. And yes, that is right: remaining in contact with God, cannot result in sinning by habit. Something can go wrong: acting in response to the flesh—which does not make someone an unbeliever, nor a regular sinner—is tantamount to not remaining in Him. This hurts the Spirit inside and by that the believer gets the strong desire to settle things righteously again.
No Bible Contradiction

1 John 3:9
With gnomic present: “No one who is born of God practices sin [already in NASB], because His seed abides in him; and he cannot sin by habit, because he is born of God.” Here also it is clear that John is not speaking from some idealistic point of view in which the Christian remains perfectly pure. And that is the way the critic reads these texts, dogmatically and totally out of proportion, instead of according to common language.
No Bible Contradiction

1 John 5:18
With gnomic present: “We know that no one who is born of God practices sin; but He [Jesus] who was born of God keeps him, and the evil one does not touch him.” Here again the theme of 1 John 3:9 is repeated and John elaborates further on it.
Later on the Christian is assured of safety against the devil as Jesus is able to protect them. The Christian is not promised a calm journey, but certainly a safe harbor.
No Bible Contradiction

Remark. Many expositors have referred to the so called durative character of the Greek present to solve the question (3:6 does not continue to sin; 3:9 continue to sin/ cannot continue to sin; 5:18 continue to sin).  


3 John 11
The saying “The one who does good is of God;” has been interpreted by the critic as meaning that good people never make mistakes. This is of course not to the point. It is contrary to common parlance to say that “good people” are sinless people. As so often the critic goes too far in his conclusions.
No Bible Contradiction