I can see how people can come to these conclusions, but from my understanding, God has a way of saying the same thing through a variety of different ways by different people, that may seem different, but is essentially the same message.
The eternal gospel message is the good news that Jesus died for our sins, that when we believe (means be live Him) and repent and turn from sin, we find eternal life in Jesus Christ. Most people leave out repentance out of this message that Christ and Paul did not. Most people don't allow the bible to define sin, which both Christ and Paul point to the same law (and others) 1 John 3:4 Rom 7:7 James 2:10-12 Mat 5:19-30 Romans 14:23
Both Christ and Paul taught this message but in slightly different ways of saying it.
Jesus: Mark 4:17 From that time Jesus began to preach and to say, “Repent, for the kingdom of heaven is at hand.”
John 11:25 Jesus said to her, “I am the resurrection and the life. He who believes in Me, though he may die, he shall live.
Luke 24: 46 Then He said to them, “Thus it is written, [
a]and thus it was necessary for the Christ to suffer and to rise from the dead the third day, 47 and that repentance and remission of sins should be preached in His name to all nations, beginning at Jerusalem.
Paul: Romans 6:1 What shall we say then? Shall we continue in sin that grace may abound? 2 Certainly not! How shall we who died to sin live any longer in it? 3 Or do you not know that as many of us as were baptized into Christ Jesus were baptized into His death? 4 Therefore we were buried with Him through baptism into death, that just as Christ was raised from the dead by the glory of the Father, even so we also should walk in newness of life.
2 Cor 7:10 For godly sorrow produces repentance
leading to salvation, not to be regretted; but the sorrow of the world produces death.
Acts 16:31 So they said, “Believe on the Lord Jesus Christ, and you will be saved, you and your household.”
Both taught the importance of the law
Jesus: John 14:15 “If you love Me, [
a]keep My commandments.
Mat 19:17 So He said to him, [
e]“Why do you call Me good? [
f]No one
is good but One,
that is, God. But if you want to enter into life, keep the commandments.” 18 He said to Him, “Which ones?” Jesus said, “‘You shall not murder,’ ‘You shall not commit adultery,’ ‘You shall not steal,’ ‘You shall not bear false witness,’ 19 ‘Honor your father and
your mother,’ and, ‘You shall love your neighbor as yourself.’ ”
Paul: 1 Cor 7:19 Circumcision is nothing and uncircumcision is nothing, but keeping the commandments of God
is what matters.
Rom 7:12 Therefore the law is holy, and the commandment holy and just and good.
Romans 2: 12 For as many as have sinned without law will also perish without law, and as many as have sinned in the law will be judged by the law 13 (for not the hearers of the law
are just in the sight of God, but the doers of the law will be justified;
Both condemned those who don't keep God's law
Jesus:
Mat 15:3 He answered and said to them, “Why do you also transgress the commandment of God because of your tradition? 4 For God commanded, saying, ‘Honor your father and your mother’; and, ‘He who curses father or mother, let him be put to death.’ 5 But you say, ‘Whoever says to his father or mother, “Whatever profit you might have received from me
is a gift
to God”— 6 then he need not honor his father [
a]or mother.’ Thus you have made the [
b]commandment of God of no effect by your tradition. 7 Hypocrites! Well did Isaiah prophesy about you, saying: 8 ‘These people [
c]draw near to Me with their mouth, And honor Me with
their lips, But their heart is far from Me. 9 And in vain they worship Me, Teaching
as doctrines the commandments of men.’
Mat 7:23 And then I will declare to them, ‘I never knew you; depart from Me, you who practice lawlessness!’
Mat 5:19 19 Whoever therefore breaks one of the least of these commandments, and teaches men so, shall be called least in the kingdom of heaven; but whoever does and teaches
them, he shall be called great in the kingdom of heaven.
Paul
Romans 2:22 You who say, “Do not commit adultery,” do you commit adultery? You who abhor idols, do you rob temples? 23 You who make your boast in the law, do you dishonor God through breaking the law?
Romans 8:7 Because the carnal mind
is enmity against God; for it is not subject to the law of God, nor indeed can be. 8 So then, those who are in the flesh cannot please God.
These are just a few examples. What sadly people do is read one of these verses and ignore the others, but they all work in harmony together. Also with Paul's writings he had to address a lot of issues with the Jews requiring Gentiles to be circumcised to be saved, which essentially means one could save themselves but we can't, we need Jesus. For example, most people will insert in Galatians the Sabbath commandment, but not once did Paul mention the Sabbath in Galatians, the main law he kept referring to was circumcision. He addressed it several times in several chapters. Many people try to insert the Sabbath when the context doesn't support it. Paul generally tells us the law he is referring to, which is also why its important to understand the differences between the law that is perfect for converting the soul written by the finger of God Psa 19:7 Exo 31:18 that is holy, just and good Rom 7:12 compared to the law of Moses that was outside the ark as a witness and against Deut 31:24-26 many confuse these laws, but the law that is perfect never becomes the law that is contrary and against and without proper understanding or caring, people will get lost with some of Paul's writings because he just uses the generic term law, but the context will tell us the law he is referring to. He was also hard to understand which doesn't help with people trying to support lawlessness, which is not what Paul taught.
Bottom line: We are not justified or saved by keeping God's law, we are saved by grace through faith. We are however Judged by the law James 2:10-12 Ecc 12:13-14 Mat 5:19-30 Rev 22:14-15 and all of us sinned and deserve the death penalty. But through the grace of God and by our faith and love in Him we can turn from our sins, repent and forsake our sins Pro 28:13 and walk in newness in Christ though His power obeying His commandments John 14:15-18, not to be saved, but because one is saved Rev 14:12. This is the faith that reconciles us Rev 22:14. Most people teach we can be saved in our sins, but we need a conversion and Jesus came to save us from sin Mat 1:21