Sounds like you misunderstand how some abuse the 1 John 5:18 verse, which that poster was trying to explain with Jesus being our Advocate to The Father for us.
It's those on the false doctrine of OSAS in the absolute sense that are guilty of abusing that 18th verse to try and say they cannot sin anymore. The 1 John 1 chapter by Apostle John showed that they can still do future sin though. So that 18th verse MUST be understood in relation to what John taught in 1 John 1 also. And this...
1 John 2:1
2 My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous:
KJV
Now think how the devil could abuse that above verse also, along with the OSAS absolutist thinking. Easy, they would say that verse further proves there's no need to inspect ourselves for future sin, because Jesus, our Advocate, has already forgiven us! But that's not how John means that above 1 John 2:1 verse, because in 1 John 1 he showed we will... still have future sin, and we need to REPENT TO JESUS about it and ask Him forgiveness.
This is a blessing. This post.
It demonstrates perfectly the anti-gospel natural man mindset.
That natural mind as God said, does not understand the things of the spirit because they are spiritually discerned. And this occurs when God's holy Spirit enters those who are his.
And this has purpose;God's.Who said,as Jesus and when asked by his disciples why he taught the gospel in parables, because his words were not meant to be understood by everyone,else they repent and be saved.
That design is extant today as well. God's will and word is eternal.
Those who disfigure the gospel don't,and will not understand even after this, that Jesus died taking the sins
of the world upon himself. He didn't take the sins in the world because then sin would not exist anymore.
He took the sins of the world. That those who believe in him are redeemed from their sins. Those sins being put under his blood that flowed from the cross so to wash us clean from what would otherwise be our sin debt to God with our blood.
That sacrifice guarantees , seals as a promise from God, eternal life for the believer.And eternal life is eternal salvation.
Because those natural minded ones are currently dead in their sins.The first death.
And when they die unredeemed from their sins, they die the second death that kills the body and the soul.
Those redeemed in Christ are eternally alive in Christ.
And all this is not our doing.
So we cannot boast,nor work to achieve salvation.
It is God's free irrevocable gift of grace he gives to we whom he calls to himself. And that he paid for by sealing the salvific covenant with his blood.
And because we are indwelt by God's holy spirit and understand the good news, we do not make a habit of sinning. Thinking we can do whatever we like now because we'll never go to hell.
Natural minds don't get that.