Romans chapter 3:10-20 is often used to justify the idea that all people are sinners, including new-born babies (notice the verbs indicated in red throughout this document, see also my article on the theory of “Original Sin”).
This interpretation stands or falls based on the exegeses of the text. With proper exegesis we can understand the purpose behind Romans. We will start with verse 9. This verse introduces the section.
In verse 9, Paul is explaining (as he did from chapter 2 on) that the Jews (as a group), although they had the advantage of receiving God’s law from Moses (Romans 3:1-2), are in no way (morally) better than the gentiles (as a group) (see also Romans 1:16). 
Paul is explaining the last part of verse 9, “they are all under sin”, in the verses that follow.
“They are all under sin” is NOT a universal statement. Paul works out what he wants to say; He says that “both Jews and Gentiles” (as 2 GROUPS, not necessarily including everyone in those GROUPS ) have been fools:
“As it is written” is a reference to the Old Testament Canon (Torah). Notice that according to the Oxford University Press edition of the Authorized King James Version, verse 10 to verse 12 refer to Psalm 14:1-3 = Psalm 53:1-3. This is also Pelagius’ opinion , my opinion (and probably the opinion of other exegetes), since the texts repeat almost the same content. In the first verses of these Psalms, it is clear that king David spoke about the fool, excluding himself, because he expresses his disappointment in, and sadness over, such people.
In Romans 3, verses 10 to 11 the fools don’t understand, seek,…
Are they born that way or did they become fools?
Verse 12 responds to this question: “They are all gone out of the way”: that means that they were once on the correct way but have gone astray. It is the same as saying: “We left Jeff’s car”, which means that at a certain moment in time, we were in Jeff’s car. That in this bible quote, it is talking about A GROUP going astray (not all individuals living in this world), is clear from the following passage: “They are TOGETHER become unprofitable” (v 12b).
Notice the same use of plurality in Romans 1:18-22? There it is also implied that they were not born fools but became fools: “THEY knew God” (! 1:21a), ” (THEY) became vain” (1:21b), “was darkened” (1:21c), “Professing THEMSELVES to be wise, they became fools” (v 22).
Verse 12c of Romans chapter 3 (“there is no one who does Good, no, not one”) to verse 18 (“there is no fear of God before their eyes”) is an explanation of the previous verses (also not a general statement but this passage is still talking about the foolish, conspiring, sinning, Jews and Gentiles). Such parts like “there is no one righteous” should not be taken out of context. Are true Christians and unborn babies also “swift to shed blood” (v15a)? Are their mouths “full of cursing and bitterness” (v14)? And maybe the most clear example of them all: Do you have the audacity to claim that “they have no fear of God before their eyes”(v18) applies to Christians??!! I hope “there is no one that doeth good, no, not one.” (v12c) does not apply to Christian individuals, or the Church of Christ as a whole! The apostle John warned us for people twisting such texts: “let no man deceive you, he that doeth righteousness is righteous, even as he (Jesus) is righteous” (1 John 3:9b)!
Verse 19a (of Romans 3) “… it says to those who are under the law” explains that the Jews (See chapter 2 for their guilt) are as guilty as the gentiles (see chapter 1 for their guilt) “that every mouth may be stopped (including the mouth of the group of the foolish Jews who have sinned in the past) and all the world (not only the mouth of the gentile group, but also the mouth of the Jewish group and vice versa).
Verse 20: Therefore the group of Jewish sinners will not be held innocent if they will now try to live strictly by the law. Those who have become ungodly cannot return to a right relationship with God, by keeping the law after having sinned. That would be like a criminal having been convicted of murder (v15), saying: “Judge, I understand but I will now live well under the law of this country, I will even clean your garden, but then you will, of course, have to let me free.” The judge might reply with something like: “Very funny Mr. X, you know well enough that you are guilty and therefore I have to send you to a lifelong prison sentence in Alcatraz. Good luck there, you will need it!”
So we have seen from verse 9 to 20 that the group of Jewish sinners should fear the Judge of Judges and Judgment Day (v 6) as much as the Gentile sinners should fear Him… They are on the same sinking ship! And they cannot escape by now starting to obey God’s law.
V 23: “For all have sinned, and come short of the glory of God” (v 23) must be viewed again in light of what we have previously seen (kept in context): “all” means (in this context) the GROUP of Gentile sinners and the GROUP of Jewish sinners.
V 21 to, and including chapter 4: But oh! Glory, glory, glory! To those who belong to the group of Jewish sinners or to those who belong to the group of Gentile sinners (not every individual, for a little child has not yet “gone out of the way” (v 12a, see all verbs indicated in red throughout this document)), who in their foolishness have sinned, and are fully responsible for it, God made a way out of their guilt and following punishment: “The righteousness of God without the law is manifested” (v 21a), “for all (both groups of sinners) have sinned and come short of the glory of God” (v 23). “Even the righteousness of God which is by faith of Jesus Christ unto all and upon all them that believe (every individual who choose to put his/her trust in Jesus Christ): for there is no difference (between both GROUPS)” (v 22). “Being justified freely (by faith/putting your trust in Jesus Christ, v22) by his grace through the redemption that is in Christ Jesus: Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God” (v 24-25). So that is how God made a way out for the GROUP of Gentile and Jewish sinners, to not have to go to “Alcatraz” (the Lake of Fire, Revelation 21:8). Paul concludes, that for those Jews and Gentiles who chose to go back to the group of innocent humans (children: Matthew 19:14, John 3:3, see verbs indicated in red, read my article on the theory of “Original Sin”), boasting is excluded, for they did not deserve Christ’s grace and forgiveness: “Where is boasting then? It is excluded. By what law? of works? Nay; but by the law of faith. Therefore we conclude that a man is justified by faith without the deeds of the law.” (v 27-28) This is applicable to both GROUPS for: “Is he the God of the Jews only? is he not also of the Gentiles? Yes, of the gentiles also: Seeing it is one God, which shall justify the circumcision by faith, and uncircumcision through faith” (v 29-30).
 The Apostle Paul is NOT talking about individuals. He is talking about 2 groups: pagan and Jewish sinners (this is very important to grasp! Read verses 9, 22-23, 29-30 of chapter 3!).
Chapter 1 talks generally about the Pagans (the pagan sinners).
Chapter 2 talks about the Jews (the fact that the Jewish sinners are as guilty as the pagan sinners in God’s eyes and they can’t therefore judge the pagan sinners “For there is no respect of persons with God” (Romans 2:11)).
In Chapter 3 Paul talks about the same thing (that the Jewish sinners have no forgiveness over the pagan sinners). The second part (from verse 21 to verse 31) shows us that for both Jewish and Gentile sinners can only be “justified freely by his (God’s) grace through the redemption that is in Christ Jesus” (v 24) “by “the righteousness of God which is by faith of Jesus Christ” (v 22a)… “for there is no difference, for all have sinned, and come short of the glory of God.” (v 22b-23) (The group of the Jews and the group of the Gentiles, not everyone).
 Pelagius, Pelagius’ Commentary on Romans, Romans 3:10.
Written by: crosstheology
Revised by: Christopher Fisher and crosstheology
All Bible verses are taken from the Authorized King James Version. Copyright public domain. Copyright the British Crown in the United Kingdom (emphases clearly indicated).