The only role we have in our salvation is we either receive it or reject it. It is totally free and offered to all and guaranteed forever. Our faith in Jesus does not hinge upon the works we do or do not do. If this was the case then no one would ever be saved because we do not seek God and even if we did we can’t work enough to please Him (c.f. Isa. 64:6).
Thankfully God has sought us out and made salvation available to all. This is evident in Scripture such as 2 Corinthians 5:21 “For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God.” Also in, Hebrews 10:12,14 “But when Christ had offered for all time a single sacrifice for sins, he sat down at the right hand of God…For by a single offering he has perfected for all time those who are being sanctified.”
These Scriptures show that Christ did what was necessary. How He made the offering and became sin so we might become righteous. As the Scripture from Hebrews points out, Jesus came to die once for man and to offer the free gift for all and for it to be all time. This is not a work of man, but God and God alone. If man had a role in the gaining or earning of salvation then yes, he could lose it. But, since man has no such role, he cannot lose salvation.
I want to leave you with a thought and a few Scriptures to ponder.
The thought is, “if we can lose our salvation or give it up does this not make our God a weak God.” If He cannot keep us once He has saved us, then that means we can slip through His hands. That would make Christ a liar and this is, of course, wrong as we read we cannot slip through His hand, and God cannot lie (John 10:28-29; Titus 1:2; Heb. 6:18). Not only this but Paul says that nothing can separate us from Him (Rom. 8:31-39). God brings us out from death and eternal separation and torment and gives us the gift of eternity that we cannot earn. God is all-powerful and He can hold you even if you think differently.
Now the final Scripture to ponder on is from Ephesians, and I know it is the most common one used for speaking against works salvation but it is relevant. “For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast” (Eph. 2:8-9). This Scripture should give comfort to those who are struggling with the thought of losing salvation. It is a gift from God, and I firmly believe that He does not take back His gifts to those whom He loves (Rom. 11:29).