The Romans 11.6 verse is very important. Simply stated, it asks, What are we depending on?
Any idea that one's salvation is a gradual process whereby, if we try hard enough, might 'get there in the end', is really a works-based religion and not Biblical. Ephesians 2.9 is perfectly clear on this.
Grace that just simply covers the debt and doesn't EMPOWER the believer to walk in newness of life and righteousness is not grace at all.
Little children,
let no one deceive you. Whoever practices righteousness is righteous, as he is righteous. 1 John 3:7(ESV)
Those who claim to be righteous, yet don't practice it are not actually righteous according to Scripture.
When salvation is reduced down to a one time transaction, rather than understanding it as 1) the event when the person believes, repents and confesses Jesus as Lord, and 2) them enduring to the end to be raised on the last day to receive the affirmative judgement. Salvation is primarily in Scripture a hope for a future event, and yet at the same time something that is enjoyed in the present. That is way the word "saved" appears in every single Greek tense in the NT.
There is no salvation for those who do not endure to the end, and for those who do not do the will of the Father.
“Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but
the one who does the will of my Father who is in heaven." Matthew 7:21(ESV)