That was addressed to people persevering: building themselves up in faith, praying, keeping in the love of God, looking for Christ's mercy.
I realize that, and it is Christ who keeps us from stumbling and who WILL present us before God the Father WITHOUT FAULT. We are kept persevering through the power of the indwelling Holy Spirit. The earlier comment was implying that only those who persevere will be saved, but God says we WILL persevere THROUGH Christ. I can't help but think we talk past each other sometimes. If you truly believe that you are saved by faith and not by your works, then the motive for good works changes from being done out of fear of hell into out of gratitude for the great love and mercy of God that gives to us eternal life. Protestants do not say works don't matter, we say works do not ADD TO the sacrifice of Christ as payment for sin and it is through our faith that God imputes the righteousness of Christ upon our souls.
That same grace that gifts to us eternal life also enables us to live in holiness and we WILL persevere because it is Christ IN us - the hope of glory. Jesus said that he would lose none of us, he will not cast us out and he will not allow us to be plucked out of his hands. Some people come back with, "we can pluck ourselves out", but that is NOT true. Jesus said he would lose NOTHING but WILL raise us up with him in glory. He is holding onto us, we are not holding onto him. We are the child and a good, loving father would never let a child hold onto his hand, he holds onto the child's. It's the same with our Heavenly Father. he disciplines and chastises, but he will never disown us. we are sealed until the day of redemption. That is HIS promise and I trust Him.