Rom 5:1, Therefore being justified by faith, we have peace with God through our Lord Jesus Christ:
Rom 5:2, By whom also we have access by faith into this grace wherein we stand, and rejoice in hope of the glory of God.
Rom 4:1, What shall we say then that Abraham our father, as pertaining to the flesh, hath found?
Rom 4:2, For if Abraham were justified by works, he hath whereof to glory; but not before God.
Rom 4:3, For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness.
Rom 4:4, Now to him that worketh is the reward not reckoned of grace, but of debt.
Rom 4:5, But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.
Rom 4:6, Even as David also describeth the blessedness of the man, unto whom God imputeth righteousness without works,
Rom 4:7, Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered.
Rom 4:8, Blessed is the man to whom the Lord will not impute sin.
These passages teach us that we have access by faith into this grace wherein we stand; and that this standing in righteousness is not based upon our performance. He "justifieth the ungodly" (Romans 4:5); and he does so because of faith in the heart of the person who is justified.
Most assuredly, being redeemed by faith will result in a changed life (2 Corinthians 5:17 (kjv)).
However, the salvation given is not based on you changing your life in order to obtain the salvation that the Lord wants to give you. Jesus catches the fish, and then He cleans them. He "justifieth the ungodly" (Romans 4:5). We are declared righteous because of faith alone; it has nothing to do with our performance. If we believe, our faith is counted for righteousness.
So then, since salvation is not based on performance, it cannot be lost because of failing in our performance.
It can only be lost because of losing faith in Jesus Christ.
And I will say that in Hebrews 3:12-13, we do find that sin is deceitful and has the power to harden us against the Lord, so that if we recklessly indulge in a sinful lifestyle, we might even lose our faith and thus our salvation.
But anyone who cleaves to Jesus (Acts of the Apostles 11:23) as an anchor of the soul (Hebrews 6:18-20) cannot lose their salvation impaho. It is only those who do not care about their salvation and who bank on OSAS doctrine and utilize that doctrine as a license for immorality, who can fall away.
Because real eternal security has to do with abiding in Christ. It is promised that the one who does the will of God abides for ever (1 John 2:17). That terminology, "for ever" is good enough for me...and it denotes the doctrine of POTS rather than OSAS. For I subscribe to the first rather than the second.
POTS (perseverance of the saints) denotes that the people involved are saints in the practical sense and that they will persevere in faith.
Whereas OSAS denotes that you can say a "sinner's prayer" and live like hell afterwards and still go to heaven.
The former is sound doctrine and encouraging to those who seek to follow the Lord.
The latter is, frankly, heresy.