So justification for eternal life can not be had even by those who have kept the law blameless as we see Zachariah and Elizabeth did in Luke1:5,6. And as Paul did in Phil.3:6. Through blameless law keeping. But, only by the faith of Christ. Gal.2:16

If they know this they sure don't show it in their doctrine. Otherwise they could never interpret Rom.3:23 to mean men fall short of the perfect standard of the law. Instead they would see the double mindedness and total contradiction they make of Paul's doctrine by interpreting "fall short" in Rom.3:23 to mean that.

Because they are unrighteous they do not see that Rom.3:23 gives testimony to the fact that sin causes the need or lack of the presence of God. Because the sin here is not believing in Jesus. Only when we believe in Jesus are we born again and have the Holy Spirit indwelling us. Which is God's glory and presence in us.

In John3:1-8 Jesus said the presence they lack can only be acquired by the new birth. And does not refer to law keeping or behavior at all. But, only to the fact that when men are born they are "not spiritual, but only natural" just as Paul says Adam was when God made him in 1Cor.15:45,46. And that this is why Paul said that sin, that is not believing in Jesus, causes men to fall short, or be in need of or lack, God's presence. Which is His glory.

We must understand that these who Paul says have sinned are those who have rejected the gospel when they heard it. And that it is because they have rejected it, and the gift of immortality offered in it, that they are in need of God's presence. Because God's presence, His glory in them, is the Holy Spirit who indwells all those who have trusted in Jesus.

But, isn't everyone in need of God's presence from conception, you ask. The short answer is yes. But, because the scripture tells us that God does not hold men accountable who can not make an informed decision, like infants and the mentally challenged, it is only those who can hear and understand the gospel that are held accountable for not believing it.

We see this in passages like Deut.1:39 and Mt.19:14 where children are not held accountable by God because they have no knowledge of good and evil. But, are considered as Jesus said in Mt.19:14 to be "of the kingdom of God".

This is not a reference to any righteousness that comes by the works of the law. It is not a reference to behavior at all. It is a reference to an innocence that is there from conception because they have no knowledge of good and evil. And remains until they are taught who Jesus is and why He came. Only then are men held to account for their own choice to believe or not believe in Jesus.

The unrighteous that ask God to make them "good enough" to be accepted into God's kingdom are asking God to do something that has no bearing on how men get to heaven. Because they believe that what they need to go to heaven is attained by works. When in truth works righteousness is just another of the many ways on the wide road that leads to destruction.

Jesus did not come to make bad people good. He did not come to make this world a better place. That is the social gospel. A gospel of works that is contrary to God's gospel of grace.

Jesus came so that mortal men could have eternal life. Heb.2:14,15 tells us plainly that "Inasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death, that is, the devil;And deliver them who through fear of death were all their lifetime subject to bondage."

This is why Gal.3:19 says God gave Israel the law "till the seed(Jesus) should come to whom the promise was made" so that they should not mingle themselves with the people of the pagan nations around them.