9 And you should not presume to say amongst yourselves: “We have Abraham as our Father”; for I tell you that out of these stones God is able to raise up children for Abraham.
This was another statement by John that would have deeply offended the Jews, Pharisees, and Sadducees.
They all held that by being the true decedents of Abraham they would automatically have a place in the Kingdom of Heaven, and that their place in Paradise was assured.
This was a very strongly held belief amongst them.
In the Talmud (a core of the teaching of Jewish Rabbis’) it is said that Abraham sits at the gates of hell to prevent any Jew from descending into hell, no matter what kind of life they have lived.
Justin Martyr (100-165 AD, a Christian apologist) said:
“That, being Abraham’s seed, though they continued in disobedience to God, and in infidelity, the kingdom of heaven should still be given them.”
Every Jew believed that they would escape the horrors of hell simple because they were directly descended from Abraham.
In some senses this is like the belief that many people have today. It is the belief that no one will go to hell, because they believe they are either good enough to earn a place in Heaven, or because God is love and will not condemn anyone to hell.
The truth is that none of us are good enough to be able to earn a place in Heaven. We only enter into Heaven through the grace of God displayed for us in Jesus, who died to pay the price of our sins.
To enter into Heaven, the narrow gate, we must repent of our sins and receive Jesus as our Lord and Saviour.
Paul emphasized this:
 God saved you by His special favour when you believed. And you can’t take credit for this; it is a gift from God.
 Salvation is not a reward for the good things we have done, so none of us can boast about it – Ephesians 2.8-9 (NLT).
God does not condemn anyone to hell; instead people condemn themselves:
18 Those who believe in Him are not judged, those who do not believe have already been judged, because they have not believed in the Name of the One and only Son of God – John 3.18.