For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast. Ephesians 2:8-9
It is a gift from God and not something we can obtain through our right actions; thus obligating God to give it to us.
Repentance (abhorring our sins and seeking God's forgiveness and help to obey His laws) and forsaking our worldly ways, faith, accepting Christ's sacrifice and coming to the knowledge of the truth are all steps in accepting His free gift. In no way do these efforts make up for our sins that caused the death of our Savior!
Once we obtain salvation our goal should be to maintain, sustain and retain it. We need help from above in order to do this. God supplies the helmet of salvation. What does salvation have to do with a helmet?
But let us who are of the day be sober, putting on the breastplate of faith and love, and as a helmet the hope of salvation. For God did not appoint us to wrath, but to obtain salvation through our Lord Jesus Christ, who died for us, that whether we wake or sleep, we should live together with Him. Therefore comfort each other and edify one another, just as you also are doing. 1 Thessalonians 5:8-11
We can receive tremendous hope and comfort by focusing on the incredible sacrifice Christ gave to save us and the amazing Kingdom that is the goal of our salvation. This hope works like a helmet to protect our minds from the discouragement and despair in this world:
I do not pray that You should take them out of the world, but that You should keep them from the evil one. They are not of the world, just as I am not of the world. John 17:15-16
Believers have been called out of this world. Though we remain in it, we are not of it and remain separate from it. Our way of living and even of thinking should differ from the world's. We are to develop the mind of Christ.
Be sober, be vigilant; because your adversary the devil walks about like a roaring lion, seeking whom he may devour. Resist him, steadfast in the faith, knowing that the same sufferings are experienced by your brotherhood in the world. 1 Peter 5:8-9
The helmet was essential for the survival of a soldier in battle. Paul, in using the word “salvation”, indicates that the helmet is a source of total deliverance. In Jesus, we can find deliverance in every situation, spiritual, emotional, and physical. He has to be our source, our guide, our “way out”. Despite our very best efforts, we save or deliver ourselves.
The New Testament tells us that we "have been saved",
But God, who is rich in mercy, because of His great love with which He loved us, even when we were dead in trespasses, made us alive together with Christ (by grace you have been saved), and raised us up together, and made us sit together in the heavenly places in Christ Jesus, that in the ages to come He might show the exceeding riches of His grace in His kindness toward us in Christ Jesus. For by grace you have been saved through faith, and that not of yourselves; it is the gift of God: Ephesians 2:4-8
Apostle Paul makes it clear that "have been saved" equates to the forgiveness of sins and coming under God's grace. We have been taken off death row.
For the message of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God. 1 Corinthians 1:18
Salvation can also describe the ongoing conversion process. Apostle Paul also calls this being "transformed by the renewing of your mind"
And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God. (Romans 12:2)
This involves having God's words written in our minds and meditating on them so we can better follow them
This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them; (Hebrews 10:16)
O how love I thy law! it is my meditation all the day. Thou through thy commandments hast made me wiser than mine enemies: for they are ever with me. I have more understanding than all my teachers: for thy testimonies are my meditation. Psalm 119:97-99
God expects us to obey His commandments. Our ultimate salvation depends on whether or not we choose to endure to the end.